Co-reporter:Zhi-Jian Zhao, Rentao Mu, Xiaohui Wang, and Jinlong Gong
Langmuir September 5, 2017 Volume 33(Issue 35) pp:8700-8700
Publication Date(Web):May 1, 2017
DOI:10.1021/acs.langmuir.7b00788
CO poisoning is a major problem for Pt-based catalysts in various catalytic processes. Thus, the prediction of CO binding energies over Pt alloy surfaces is fundamentally important to evaluate their CO poisoning tolerance. This article describes the effect of surface and subsurface coordination environments on the CO binding strength over PtCu alloy surfaces by employing density functional theory calculations. We show that the existence of surface Pt neighbors weakens the CO binding strength on Pt, whereas the subsurface Pt neighbors play the opposite role. Crystal orbital Hamilton population analysis suggests a stronger antibonding interaction for the Ptsurface–Ptsubsurface bond than for the Ptsurface–Ptsurface bond, which indicates less stable subsurface Pt atoms that hence generate an activated surface Pt that attracts CO more strongly. On the basis of the calculated CO binding energies, an empirical formula, with Pt–Pt coordination numbers as the variables, has been fitted to achieve a fast prediction of CO binding energy over PtCu alloy surfaces.
Co-reporter:Tuo Wang
Science China Materials 2017 Volume 60( Issue 1) pp:90-92
Publication Date(Web):2017 January
DOI:10.1007/s40843-016-5158-0
Co-reporter:Ke Dang, Tuo Wang, Chengcheng Li, Jijie Zhang, ... Jinlong Gong
Engineering 2017 Volume 3, Issue 3(Volume 3, Issue 3) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/J.ENG.2017.03.005
This paper describes the combinational surface kinetics enhancement and surface states passivation of nickel-borate (Ni-Bi) co-catalyst for a hematite (Fe2O3) photoanode. The Ni-Bi-modified Fe2O3 photoanode exhibits a cathodic onset potential shift of 230 mV and a 2.3-fold enhancement of the photocurrent at 1.23 V, versus the reversible hydrogen electrode (RHE). The borate (Bi) in the Ni-Bi film promotes the release of protons for the oxygen evolution reaction (OER).
Co-reporter:Jinmeng Cai, Moqing Wu, Yating Wang, Hao Zhang, ... Jinlong Gong
Chem 2017 Volume 2, Issue 6(Volume 2, Issue 6) pp:
Publication Date(Web):8 June 2017
DOI:10.1016/j.chempr.2017.05.006
•Tuning the macropores of PCs can obtain enhanced light harvesting•Defects in the disordered surface layer benefit the charge separation•A synergistic enhancement was achieved in this dual-functional structurePhotocatalytic water splitting with solar light has been considered the ultimate green and sustainable route for the production of a clean and renewable hydrogen resource. However, the overall low efficiency is still a great challenge for industrial applications. Developing highly efficient photocatalysts with enhanced light harvesting and low recombination of charge carriers is crucial to solving the problem. Black TiO2 with a hydrogenation-induced surface disorder is now a research hotspot because of the efficient charge separation efficiency. The slow photon effect of the photonic crystals can greatly enhance light harvesting. This paper describes a coupling strategy of the disorder-engineered surface and the slow photon effect, which synergistically improved the photocatalytic performance. This approach of the as-proposed catalyst design and preparation strategy could be extended to other photocatalytic systems for use of solar energy.Solar light harvesting and charge separation are both critical to the solar-to-energy conversion in photocatalysis, but it is difficult to simultaneously achieve both in a single-component material. This paper describes the design and synthesis of dual-functional surface-disorder-engineered titanium dioxide photonic crystals (TiO2 PCs) for efficient solar light harvesting and charge separation in photocatalytic hydrogen evolution. The slow photon effect of TiO2 PCs enhances the photon-matter interaction to increase light harvesting, and the disorder-engineered surface layer can form band tail states and trap centers to promote the separation and inhibit the recombination of charge carriers. The synergetic enhancement of light harvesting and charge separation in this single-component material leads to a high performance toward photocatalytic hydrogen evolution. This approach provides a promising strategy for designing dual-functional materials with a high solar-to-energy conversion efficiency for various photocatalytic processes.Download high-res image (258KB)Download full-size image
Co-reporter:Hao Tian;Xinyu Li;Sai Chen;Liang Zeng
Chinese Journal of Chemistry 2017 Volume 35(Issue 5) pp:651-658
Publication Date(Web):2017/05/01
DOI:10.1002/cjoc.201600569
Reducible oxides (e.g., CeO2 and ZrO2) supported 3d transition metals (e.g., Ni, Co, Pt) exhibit remarkable catalytic activity in reactions that involve water activation, such as steam reforming and water gas shift. This paper describes the influence of Sn addition on the performance of Ni/CeO2 catalysts in ethanol steam reforming. 0.25 wt% Sn addition improved the stability of Ni/CeO2 by forming Ni-Sn bimetallic nanoparticles with Sn enriched surfaces to suppress the carbon deposition. Ni0.25Sn/CeO2 kept over 90% ethanol conversion in a 20 h stability test at 600 °C with over 60% hydrogen selectivity under a gas hourly space velocity of 57000 mL/(g•h). However, the presence of Sn decreased the overall oxygen storage capacity and oxygen mobility of NiSn/CeO2, which hampered water activation process and coke elimination occurring at the interface between Ni and CeO2. Additionally, ethanol decomposition was also suppressed due to the coverage of Sn atoms on Ni surfaces.
Co-reporter:Zhibin Luo;Dr. Tuo Wang;Jijie Zhang;Chengcheng Li;Huimin Li; Dr. Jinlong Gong
Angewandte Chemie International Edition 2017 Volume 56(Issue 42) pp:12791-12791
Publication Date(Web):2017/10/09
DOI:10.1002/anie.201708426
The modification of a hematite nanoarray photoanode with a TiO2 interlayer by atomic layer deposition is described by J. Gong and co-workers in their Communication on page 12908 ff. This interlayer serves as both a passivation layer and a Ti4+ dopant source for the bulk hematite; it suppresses interfacial charge recombination and simultaneously improves the hematite bulk conductivity. A very high photocurrent for photoelectrochemical (PEC) water oxidation was achieved with this dendritic hematite photoanode upon addition of an iron oxide hydroxide co-catalyst.
Co-reporter:Dr. Lei Zhang; Zhi-Jian Zhao; Jinlong Gong
Angewandte Chemie 2017 Volume 129(Issue 38) pp:11482-11511
Publication Date(Web):2017/09/11
DOI:10.1002/ange.201612214
AbstractDie allmählich zunehmende Konzentration an Kohlendioxid (CO2) in der Atmosphäre wurde als Hauptursache für den Anstieg der mittleren Erdtemperatur erkannt. In den letzten Jahren hat daher die Entwicklung von Wegen zur hocheffizienten Umwandlung von CO2 viel Beachtung gefunden. Dieser Aufsatz beschreibt neueste Fortschritte auf dem Gebiet von Festkörperkatalysatoren für die elektrochemische CO2-Reduktion. Die Bedeutung dieser katalytischen Verfahren wird im Einführungsteil dargestellt, darauf folgen die allgemeinen Parameter für die elektrochemische CO2-Reduktion und ein Überblick zur Reaktionsvorrichtung. Wir erörtern außerdem verschiedene Arten von festen Katalysatoren in Abhängigkeit von den Mechanismen der CO2-Umwandlung. Darüber hinaus geben wir eine Zusammenfassung zu den entscheidenden Faktoren (Partikelgröße, Oberflächenstruktur, Zusammensetzung usw.), die die Leistungsfähigkeit der elektrochemischen Reduktion bestimmen.
Co-reporter:Zhibin Luo;Dr. Tuo Wang;Jijie Zhang;Chengcheng Li;Huimin Li; Dr. Jinlong Gong
Angewandte Chemie International Edition 2017 Volume 56(Issue 42) pp:12878-12882
Publication Date(Web):2017/10/09
DOI:10.1002/anie.201705772
AbstractThis paper describes the introduction of a thin titanium dioxide interlayer that serves as passivation layer and dopant source for hematite (α-Fe2O3) nanoarray photoanodes. This interlayer is demonstrated to boost the photocurrent by suppressing the substrate/hematite interfacial charge recombination, and to increase the electrical conductivity by enabling Ti4+ incorporation. The dendritic nanostructure of this photoanode with an increased solid–liquid junction area further improves the surface charge collection efficiency, generating a photocurrent of about 2.5 mA cm−2 at 1.23 V versus the reversible hydrogen electrode (vs. RHE) under air mass 1.5G illumination. A photocurrent of approximately 3.1 mA cm−2 at 1.23 V vs. RHE could be achieved by addition of an iron oxide hydroxide cocatalyst.
Co-reporter:Zhibin Luo;Dr. Tuo Wang;Jijie Zhang;Chengcheng Li;Huimin Li; Dr. Jinlong Gong
Angewandte Chemie 2017 Volume 129(Issue 42) pp:13058-13062
Publication Date(Web):2017/10/09
DOI:10.1002/ange.201705772
AbstractThis paper describes the introduction of a thin titanium dioxide interlayer that serves as passivation layer and dopant source for hematite (α-Fe2O3) nanoarray photoanodes. This interlayer is demonstrated to boost the photocurrent by suppressing the substrate/hematite interfacial charge recombination, and to increase the electrical conductivity by enabling Ti4+ incorporation. The dendritic nanostructure of this photoanode with an increased solid–liquid junction area further improves the surface charge collection efficiency, generating a photocurrent of about 2.5 mA cm−2 at 1.23 V versus the reversible hydrogen electrode (vs. RHE) under air mass 1.5G illumination. A photocurrent of approximately 3.1 mA cm−2 at 1.23 V vs. RHE could be achieved by addition of an iron oxide hydroxide cocatalyst.
Co-reporter:Zhibin Luo;Dr. Tuo Wang;Jijie Zhang;Chengcheng Li;Huimin Li; Dr. Jinlong Gong
Angewandte Chemie 2017 Volume 129(Issue 42) pp:12967-12967
Publication Date(Web):2017/10/09
DOI:10.1002/ange.201708426
Verzweigte Hämatit-Photoanoden wurden durch Atomlagenabscheidung mit einer dünnen Trennschicht aus Titandioxid modifiziert. In der Zuschrift auf S. 13058 ff. zeigen J. Gong et al., dass diese Trennschicht als Passivierungsschicht und Dotierungsquelle dient. So unterdrückt sie die Ladungsrekombination an der Grenzfläche und verbessert die elektrische Leitfähigkeit. Mithilfe eines Cokatalysators aus Eisenoxidhydroxid wurde mit dieser verzweigten Hämatit-Photoanode ein sehr hoher Photostrom in der photoelektrochemischen (PEC-)Wasseroxidation erzielt.
Co-reporter:Congling Hu;Lei Zhang;Zhi-Jian Zhao;Jun Luo;Jing Shi;Zhiqi Huang
Advanced Materials 2017 Volume 29(Issue 36) pp:
Publication Date(Web):2017/09/01
DOI:10.1002/adma.201701820
Transition-metal oxides are extensively investigated as efficient electrocatalysts for the oxygen evolution reaction (OER). However, large-scale applications remain challenging due to their moderate catalytic activity. Optimized regulation of surface states can lead to improvement of catalytic properties. Here, the design of Mn@CoxMn3−xO4 nanoparticles with abundant edge sites via a simple seed-mediated growth strategy is described. The unsaturated coordination generated on the edge sites of CoxMn3−xO4 shells makes a positive contribution to the surface-structure tailoring. Density functional theory calculations indicate that the edge sites with unsaturated coordination exhibit intense affinity for OH− in the alkaline electrolyte, which greatly enhances the electrochemical OER performance of the catalysts. The resulting Mn@CoxMn3−xO4 catalysts yield a current density of 10 mA cm−2 at an overpotential of 246 mV and a relatively low Tafel slope of 46 mV dec−1. The successful synthesis of these metal oxides nanoparticles with edge sites may pave a new path for rationally fabricating efficient OER catalysts.
Co-reporter:Xinyu Li, Di Li, Hao Tian, Liang Zeng, Zhi-Jian Zhao, Jinlong Gong
Applied Catalysis B: Environmental 2017 Volume 202(Volume 202) pp:
Publication Date(Web):1 March 2017
DOI:10.1016/j.apcatb.2016.09.071
•La2O2CO3 nanorods are used as support precursor to stabilize Ni nanoparticles.•The support provide abundant medium basic sites to facilitate CO2 adsorption.•The enhanced interaction between Ni and La2O3 restricts the growth of nickel particles.•The La2O2CO3 formation during the DRM process eliminates the coke deposition.This paper describes the design of a Ni/La2O3 catalyst using La2O2CO3 nanorod as a support precursor (denoted as Ni/La2O3-LOC) via a wet impregnation method for dry reforming of methane (DRM). The results showed that La2O3 derived from the La2O2CO3 precursor maintained its initial morphology upon thermal treatment and could highly disperse Ni particles on it. Additionally, the nanorod-shaped support could provide more medium-strength basic sites to facilitate CO2 adsorption and activation on its surface. Consequently, the Ni/La2O3-LOC catalyst reached 70% of CH4 conversion and 75% of CO2 conversion at 700 °C after 50 h DRM reaction with a H2/CO ratio of 0.87. The enhanced metal-support interaction restricted the sintering of nickel particles under harsh reaction conditions. Coke evolution on the catalysts was also investigated to understand coke formation mechanism and the role of La2O2CO3 in coke elimination. It has been found that nickel dispersion can affect distribution of coke and La2O2CO3 on the surface of catalyst, both of which have a close relation with catalytic performance.Download high-res image (177KB)Download full-size image
Co-reporter:Xiaoyi Li;Dang-guo Cheng;Zhi-Jian Zhao;Fengqiu Chen
Reaction Chemistry & Engineering (2016-Present) 2017 vol. 2(Issue 2) pp:215-225
Publication Date(Web):2017/04/04
DOI:10.1039/C6RE00179C
This paper describes the observation of an irregular decrease in 1-butene conversion during oxidative dehydrogenation over ZnFe2O4 in the production of 1,3-butadiene upon increasing the reaction temperature above 400 °C. Mono and multi-pulse adsorption and reoxidation were developed to determine the reaction mechanism that led to this phenomenon. Adsorbed species were found to be generated by 1-butene adsorption, which blocked the active sites, and with higher reaction temperatures, the surface reconstruction of the catalyst could lead to catalyst deactivation. Temperature-programmed oxidation revealed the correlation between different adsorbed species and the corresponding altered active sites. A temperature-induced surface reconstruction mechanism to explain the possible deactivation was then proposed and confirmed with X-ray photoelectron spectroscopy. The original spinel surface structure of the catalyst was transformed into cubic cells formed by Zn2+ and Fe2+ after the initiation of adsorption at high temperatures, which resulted in its final deactivation.
Co-reporter:Ke Dang;Xiaoxia Chang;Tuo Wang
Nanoscale (2009-Present) 2017 vol. 9(Issue 42) pp:16133-16137
Publication Date(Web):2017/11/02
DOI:10.1039/C7NR06636H
This paper describes an amorphous nickel boride (NiB) electrocatalyst loaded on porous bismuth vanadate (BiVO4) with high activity for oxygen evolution in photoelectrochemical water oxidation. The NiB-decorated BiVO4 photoanode exhibits an onset potential of 0.25 V versus the reversible hydrogen electrode (vs. RHE) and a photocurrent of 3.47 mA cm−2 at 1.23 V vs. RHE under simulated 100 mW cm−2 irradiation.
Co-reporter:Rentao Mu;Zhi-jian Zhao;Zdenek Dohnálek
Chemical Society Reviews 2017 vol. 46(Issue 7) pp:1785-1806
Publication Date(Web):2017/04/03
DOI:10.1039/C6CS00864J
Understanding water/solid interactions is of great importance in a variety of fundamental and technological processes, such as photocatalytic water splitting, heterogeneous catalysis, electrochemistry, and corrosion. This review describes recent advancements in the molecular-level understanding of water adsorption, dissociation and clustering on model surfaces of metal oxides, achieved primarily by combining scanning probe microscopies with ensemble-averaged techniques and density functional theory calculations. Factors controlling how water binds and clusters on the coordinatively unsaturated metal cations of different oxide surfaces are discussed. We start by reviewing the fundamental differences in the relative stability of molecularly and dissociatively-bonded water monomers and clusters on isostructural rutile TiO2(110) and RuO2(110) surfaces and on different surfaces and polymorphs of TiO2. We further discuss how oxide interfaces (both exposed and buried) with metals affect water dissociation. Subsequently, we focus on high coverage water overlayers such as one-dimensional water chain structures that result from different substrate morphologies, and water monolayer structures. We conclude with novel studies of interfacial water in liquids.
Co-reporter:Jinlong Gong;Xinhe Bao
Chemical Society Reviews 2017 vol. 46(Issue 7) pp:1770-1771
Publication Date(Web):2017/04/03
DOI:10.1039/C7CS90022H
Surface and interfacial catalysis plays a vital role in chemical industries, electrochemistry and photochemical reactions. The challenges of modern chemistry are to optimize the chemical reaction processes and understand the detailed mechanism of chemical reactions. Since the early 1960s, the foundation of surface science systems has allowed the study of surface and interfacial phenomena on atomic/molecular level, and thus brought a number of significant developments to fundamental and technological processes, such as catalysis, material science and biochemistry, just to name a few. This themed issue describes the recent advances and developments in the fundamental understanding of surface and interfacial catalysis, encompassing areas of knowledge from metal to metal oxide, carbide, graphene, hexagonal boron nitride, and transition metal dichalcogenides under ultrahigh vacuum conditions, as well as under realistic reaction conditions.
Co-reporter:Zhibin Luo;Chengcheng Li;Shanshan Liu;Tuo Wang
Chemical Science (2010-Present) 2017 vol. 8(Issue 1) pp:91-100
Publication Date(Web):2016/12/19
DOI:10.1039/C6SC03707K
Hematite (α-Fe2O3) is a promising candidate for solar-to-hydrogen energy conversion. However, the low carrier mobility and extremely high charge recombination rate limit the practical application of hematite in solar water splitting. This paper describes the fabrication of a Fe2O3 photoanode with gradient incorporation of phosphorus (P) employing a facile dipping and annealing method to improve the charge separation for enhanced photoelectrochemical water oxidation. This gradient P incorporation increases the width of band bending over a large region in Fe2O3, which is crucial for promoting the charge separation efficiency in the bulk. Although both gradient and homogeneous P-incorporated Fe2O3 samples exhibit similar electrical conductivity, the Fe2O3 electrode with a gradient P concentration presents an additional charge separation effect. A photocurrent of ∼1.48 mA cm−2 is obtained at 1.23 V vs. reversible hydrogen electrode (vs. RHE) under air mass 1.5G illumination. Additionally, the H2O oxidation kinetics of Fe2O3 with gradient P incorporation was further improved upon loading cobalt phosphate as cocatalyst, reaching a photocurrent of ∼2.0 mA cm−2 at 1.23 V vs. RHE.
Co-reporter:Shengbo Zhang;Hua Wang;Mei Li;Jinyu Han;Xiao Liu
Chemical Science (2010-Present) 2017 vol. 8(Issue 6) pp:4489-4496
Publication Date(Web):2017/05/30
DOI:10.1039/C7SC00713B
Heterogeneous metal complex catalysts for direct C–H activation with high activity and durability have always been desired for transforming raw materials into feedstock chemicals. This study described the design and synthesis of one-dimensional organosilica nanotubes containing 2,2′-bipyridine (bpy) ligands in the framework (BPy-NT) and their post-synthetic metalation to provide highly active and robust molecular heterogeneous catalysts. By adjusting the ratios of organosilane precursors, very short BPy-NT with ∼50 nm length could be controllably obtained. The post-synthetic metalation of bipyridine-functionalized nanotubes with [IrCp*Cl(μ-Cl)]2 (Cp* = η5-pentamethylcyclopentadienyl) and [Ir(cod)(OMe)]2 (cod = 1,5-cyclooctadiene) afforded solid catalysts, IrCp*-BPy-NT and Ir(cod)-BPy-NT, which were utilized for C–H oxidation of heterocycles and cycloalkanes as well as C–H borylation of arenes. The cut-short nanotube catalysts displayed enhanced activities and durability as compared to the analogous homogeneous catalysts and other conventional heterogeneous catalysts, benefiting from the isolated active sites as well as the fast transport of substrates and products. After the reactions, a detailed characterization of Ir-immobilized BPy-NT via TEM, SEM, nitrogen adsorption, UV/vis, XPS, and 13C CP MAS NMR indicated the molecular nature of the active species as well as stable structures of nanotube scaffolds. This study demonstrates the potential of BPy-NT with a short length as an integration platform for the construction of efficient heterogeneous catalytic systems for organic transformations.
Co-reporter:Di Li, Xinyu Li, and Jinlong Gong
Chemical Reviews 2016 Volume 116(Issue 19) pp:11529-11653
Publication Date(Web):August 16, 2016
DOI:10.1021/acs.chemrev.6b00099
This Review describes recent advances in the design, synthesis, reactivity, selectivity, structural, and electronic properties of the catalysts for reforming of a variety of oxygenates (e.g., from simple monoalcohols to higher polyols, then to sugars, phenols, and finally complicated mixtures like bio-oil). A comprehensive exploration of the structure–activity relationship in catalytic reforming of oxygenates is carried out, assisted by state-of-the-art characterization techniques and computational tools. Critical emphasis has been given on the mechanisms of these heterogeneous-catalyzed reactions and especially on the nature of the active catalytic sites and reaction pathways. Similarities and differences (reaction mechanisms, design and synthesis of catalysts, as well as catalytic systems) in the reforming process of these oxygenates will also be discussed. A critical overview is then provided regarding the challenges and opportunities for research in this area with a focus on the roles that systems of heterogeneous catalysis, reaction engineering, and materials science can play in the near future. This Review aims to present insights into the intrinsic mechanism involved in catalytic reforming and provides guidance to the development of novel catalysts and processes for the efficient utilization of oxygenates for energy and environmental purposes.
Co-reporter:Lei Zhang, Zhaoxiong Xie and Jinlong Gong
Chemical Society Reviews 2016 vol. 45(Issue 14) pp:3916-3934
Publication Date(Web):20 Apr 2016
DOI:10.1039/C5CS00958H
Au–Pd nanostructured materials have been recognized as important heterogeneous catalysts in various reactions, due to their superior activities caused by the ensemble and ligand effects. In recent years, shape-controlled synthesis of noble metal nanocrystals (NCs) provided a brand-new insight for improving the performance of catalysts. The electronic properties and catalytic activities of Au–Pd NCs could be optimized by tuning their shape and composition engineering. This review describes recent progress in the design and synthesis of shape-controlled Au–Pd bimetallic NCs and their emerging catalytic applications. The review starts with a general discussion of various applications of Au–Pd catalysts and the significance of preparing shape-controlled Au–Pd NCs, followed by an overview of synthetic strategies for two different structures of Au–Pd bimetallic catalysts: a core–shell structure and an alloy structure. We also put forward the key factors for the preparation of Au–Pd core–shell and alloy structures. Additionally, we discussed the unique optical properties and structural effects of shape-controlled Au–Pd NCs. These recent advancements in the methodology development of Au–Pd bimetallic NCs offer numerous insights for generating Au–Pd NCs with a number of unique geometries in the future. Furthermore, the systematic synthesis of core–shell or alloy structures would provide insights for the preparation of other bimetallic NCs.
Co-reporter:Xiaoxia Chang, Tuo Wang and Jinlong Gong
Energy & Environmental Science 2016 vol. 9(Issue 7) pp:2177-2196
Publication Date(Web):17 Mar 2016
DOI:10.1039/C6EE00383D
Large amounts of anthropogenic CO2 emissions associated with increased fossil fuel consumption have led to global warming and an energy crisis. The photocatalytic reduction of CO2 into solar fuels such as methane or methanol is believed to be one of the best methods to address these two problems. In addition to light harvesting and charge separation, the adsorption/activation and reduction of CO2 on the surface of heterogeneous catalysts remain a scientifically critical challenge, which greatly limits the overall photoconversion efficiency and selectivity of CO2 reduction. This review describes recent advances in the fundamental understanding of CO2 photoreduction on the surface of heterogeneous catalysts and particularly provides an overview of enhancing the adsorption/activation of CO2 molecules. The reaction mechanism and pathways of CO2 reduction as well as their dependent factors are also analyzed and discussed, which is expected to enable an increase in the overall efficiency of CO2 reduction through minimizing the reaction barriers and controlling the selectivity towards the desired products. The challenges and perspectives of CO2 photoreduction over heterogeneous catalysts are presented as well.
Co-reporter:Peng Zhang, Tuo Wang, Xiaoxia Chang, and Jinlong Gong
Accounts of Chemical Research 2016 Volume 49(Issue 5) pp:911
Publication Date(Web):April 14, 2016
DOI:10.1021/acs.accounts.6b00036
Continuous efforts have been devoted to searching for sustainable energy resources to alleviate the upcoming energy crises. Among various types of new energy resources, solar energy has been considered as one of the most promising choices, since it is clean, sustainable, and safe. Moreover, solar energy is the most abundant renewable energy, with a total power of 173 000 terawatts striking Earth continuously. Conversion of solar energy into chemical energy, which could potentially provide continuous and flexible energy supplies, has been investigated extensively. However, the conversion efficiency is still relatively low since complicated physical, electrical, and chemical processes are involved. Therefore, carefully designed photocatalysts with a wide absorption range of solar illumination, a high conductivity for charge carriers, a small number of recombination centers, and fast surface reaction kinetics are required to achieve a high activity.This Account describes our recent efforts to enhance the utilization of charge carriers for semiconductor photocatalysts toward efficient solar-to-chemical energy conversion. During photocatalytic reactions, photogenerated electrons and holes are involved in complex processes to convert solar energy into chemical energy. The initial step is the generation of charge carriers in semiconductor photocatalysts, which could be enhanced by extending the light absorption range. Integration of plasmonic materials and introduction of self-dopants have been proved to be effective methods to improve the light absorption ability of photocatalysts to produce larger amounts of photogenerated charge carriers. Subsequently, the photogenerated electrons and holes migrate to the surface. Therefore, acceleration of the transport process can result in enhanced solar energy conversion efficiency. Different strategies such as morphology control and conductivity improvement have been demonstrated to achieve this goal. Fine-tuning of the morphology of nanostructured photocatalysts can reduce the migration distance of charge carriers. Improving the conductivity of photocatalysts by using graphitic materials can also improve the transport of charge carriers. Upon charge carrier migration, electrons and holes also tend to recombine. The suppression of recombination can be achieved by constructing heterojunctions that enhance charge separation in the photocatalysts. Surface states acting as recombination centers should also be removed to improve the photocatalytic efficiency. Moreover, surface reactions, which are the core chemical processes during the solar energy conversion, can be enhanced by applying cocatalysts as well as suppressing side reactions. All of these strategies have been proved to be essential for enhancing the activities of semiconductor photocatalysts. It is hoped that delicate manipulation of photogenerated charge carriers in semiconductor photocatalysts will hold the key to effective solar-to-chemical energy conversion.
Co-reporter:Zhiqi Huang; David Raciti; Shengnan Yu; Lei Zhang; Lin Deng; Jie He; Yijing Liu; Niveeen M. Khashab; Chao Wang; Jinlong Gong;Zhihong Nie
Journal of the American Chemical Society 2016 Volume 138(Issue 20) pp:6332-6335
Publication Date(Web):April 19, 2016
DOI:10.1021/jacs.6b01328
Metallic nanotubes represent a class of hollow nanostructures with unique catalytic properties. However, the wet-chemical synthesis of metallic nanotubes remains a substantial challenge, especially for those with dimensions below 50 nm. This communication describes a simultaneous alloying-etching strategy for the synthesis of Pt nanotubes with open ends by selective etching Au core from coaxial Au/Pt nanorods. This approach can be extended for the preparation of Pt nanorings when Saturn-like Au core/Pt shell nanoparticles are used. The diameter and wall thickness of both nanotubes and nanorings can be readily controlled in the range of 14–37 nm and 2–32 nm, respectively. We further demonstrated that the nanotubes with ultrathin side walls showed superior catalytic performance in oxygen reduction reaction.
Co-reporter:Lei Zhang, Shengnan Yu, Jijie Zhang and Jinlong Gong
Chemical Science 2016 vol. 7(Issue 6) pp:3500-3505
Publication Date(Web):14 Mar 2016
DOI:10.1039/C6SC00083E
Au–Pt bimetallic structures can effectively improve the activity and stability of catalysts in several fuel cell related electrochemical reactions. However, most of the methods for the preparation of Au–Pt nanocrystals (NCs) with core–shell structures are step-wise syntheses, which are adverse for reducing the production costs and the scale-up process. This paper describes a one-pot synthesis of rhombic dodecahedral AuPt@Pt bimetallic nanocrystals with dendritic branches. The dendritic branches on the surfaces were grown through oriented attachment and the whole particle exhibited a single-crystal structure. The thickness of the dendritic Pt shell can be controlled by tuning the introduced Pt precursor. With the Au-enhancement effect arising from the Au–Pt bimetallic core and high atom utilization efficiency provided by the porous structure, the AuPt@Pt bimetallic NCs exhibited greatly enhanced electrocatalytic properties (e.g. oxygen reduction reaction and formic acid oxidation) than those of the commercial Pt/C catalyst.
Co-reporter:Ang Li, Tuo Wang, Xiaoxia Chang, Weiting Cai, Peng Zhang, Jijie Zhang and Jinlong Gong
Chemical Science 2016 vol. 7(Issue 2) pp:890-895
Publication Date(Web):26 Nov 2015
DOI:10.1039/C5SC04163E
Efficient charge separation is a critical factor for solar energy conversion by heterogeneous photocatalysts. This paper describes the complete spatial separation of oxidation and reduction cocatalysts to enhance the efficacy of charge separation and surface reaction. Specifically, we design Pt@TiO2@MnOx hollow spheres (PTM-HSs) with Pt and MnOx loaded onto the inner and outer surface of TiO2 shells, respectively. Pt favours electron trapping, while MnOx tends to collect holes. Upon generation from TiO2, electrons and holes flow inward and outward of the spherical photocatalyst, accumulating on the corresponding cocatalysts, and then take part in redox reactions. Combined with other advantages, such as the large surface area and appropriate pore size, the PTM-HSs exhibit high efficiency for the photocatalytic oxidation of water and benzyl alcohol. The mechanism of the oxidation process of benzyl alcohol over the photocatalyst is also presented.
Co-reporter:Gang Liu, Liang Zeng, Zhi-Jian Zhao, Hao Tian, Tengfang Wu, and Jinlong Gong
ACS Catalysis 2016 Volume 6(Issue 4) pp:2158
Publication Date(Web):February 22, 2016
DOI:10.1021/acscatal.5b02878
Compared to metallic platinum and chromium oxide, zinc oxide (ZnO) is an inexpensive and low-toxic alternative for the direct dehydrogenation of propane (PDH). However, besides the limited activity, conventional zinc-based catalysts suffer from serious deactivation, because of ZnO reduction and/or carbon deposition. Considering the high cost of platinum, reducing the amount of platinum in the catalyst is always desirable. This paper describes a catalyst comprising ZnO modified by trace platinum supported on Al2O3, where the Zn2+ species serve as active sites and platinum acts as a promoter. This catalyst contains less platinum than traditional platinum-based catalysts and is much more stable than conventional ZnO catalyst or commercial chromium-based systems during PDH. It is proposed that ZnO was promoted to a stronger Lewis acid by platinum; thus, easier C–H activation and accelerated H2 desorption were achieved.Keywords: heterogeneous catalysis; hydrogen desorption; Lewis acid; platinum; propane dehydrogenation; ZnO catalyst
Co-reporter:Gang Liu, Zhi-Jian Zhao, Tengfang Wu, Liang Zeng, and Jinlong Gong
ACS Catalysis 2016 Volume 6(Issue 8) pp:5207
Publication Date(Web):June 28, 2016
DOI:10.1021/acscatal.6b00893
Supported VOx catalysts are promising for use in propane dehydrogenation (PDH) because of the relatively superior activity and stable performance upon regeneration. However, the nature of the active sites and reaction mechanism during PDH over VOx-based catalysts remains elusive. We examined active species by attaining various fractions of V5+, V4+, and V3+ ions by adjusting the surface vanadium density on an alumina support. The results reveal a close relationship between TOF and the fraction of V3+ ion, indicating that V3+ was more active for PDH. In situ diffuse reflectance infrared Fourier transform spectroscopy showed the same strong adsorbed species during both propane dehydrogenation and propylene hydrogenation. The results indicated that such an intermediate may correspond to V species containing a C═C bond, i.e., V–C3H5, and a reaction mechanism was proposed accordingly.Keywords: DRIFTS; oxidation states; propane dehydrogenation (PDH); reaction mechanism; vanadium oxide
Co-reporter:Tuo Wang, Hongyan Ma, Liang Zeng, Di Li, Hao Tian, Shengning Xiao and Jinlong Gong
Nanoscale 2016 vol. 8(Issue 19) pp:10177-10187
Publication Date(Web):12 Apr 2016
DOI:10.1039/C6NR02586B
This paper describes the design of high-loading Ni/Al2O3 catalysts (78 wt% Ni) for low temperature ethanol steam reforming. The catalysts were synthesized via both co-precipitation (COP) and impregnation (IMP) methods. All the catalysts were measured by N2 adsorption–desorption, XRD, H2-TPR, and H2 pulse chemisorption. The characterization results demonstrated that the preparation method and the loading significantly affected the nickel particle size, active nickel surface area and catalytic performance. Over COP catalysts, large nickel particles were presented in nickel aluminum mixed oxides. In comparison, IMP catalysts gained more “free” NiO particles with weak interaction with the aluminum oxide. Consequently, COP catalysts yielded smaller nickel particles and larger active nickel surface areas than those of IMP catalysts. High loading is beneficial for obtaining sufficient active nickel sites when nickel particles are dispersed via COP, whereas excessive nickel content is not desired for catalysts prepared by IMP. Specifically, the 78 wt% nickel loaded catalyst synthesized by COP possessed small nickel particles (∼6.0 nm) and an abundant active nickel area (35.1 m2 gcat−1). Consequently, COP-78 achieved superior stability with 92% ethanol conversion and ∼35% H2 selectivity at 673 K for 30 h despite the presence of a considerable amount of coke.
Co-reporter:Peng Zhang, Tuo Wang and Jinlong Gong
Chemical Communications 2016 vol. 52(Issue 57) pp:8806-8809
Publication Date(Web):03 Jun 2016
DOI:10.1039/C6CC03411J
This paper describes the fabrication of TiO2 overlayers by atomic layer deposition to passivate the surface states on Ta3N5 thin film anodes for photoelectrochemical water oxidation. The removal of surface states reduces the overpotential and decreases the density of surface recombination centers, resulting in enhanced activity through effective utilization of photogenerated charge carriers.
Co-reporter:Zhibin Luo, Chengcheng Li, Dong Zhang, Tuo Wang and Jinlong Gong
Chemical Communications 2016 vol. 52(Issue 58) pp:9013-9015
Publication Date(Web):07 Dec 2015
DOI:10.1039/C5CC09321J
This paper describes the design and synthesis of a heterojunction photoanode composed of highly-oriented Fe2O3/ZnFe2O4 nanocolumnar arrays with a well-defined morphology by reactive ballistic deposition and atomic layer deposition. This specific structure enhances the charge separation at the Fe2O3/ZnFe2O4 interface, leading to an improved photoelectrochemical performance for water oxidation.
Co-reporter:Dr. Peng Zhang; Tuo Wang;Xiaoxia Chang; Lei Zhang ; Jinlong Gong
Angewandte Chemie International Edition 2016 Volume 55( Issue 19) pp:5851-5855
Publication Date(Web):
DOI:10.1002/anie.201600918
Abstract
Cocatalysis plays an important role in enhancing the activity of semiconductor photocatalysts for solar water splitting. Compared to a single cocatalyst configuration, a cocatalytic system consisting of multiple components with different functions may realize outstanding enhancement through their interactions, yet limited research has been reported. Herein we describe the synergistic cocatalytic effect between carbon nanodots (CDots) and Co3O4, which promotes the photoelectrochemical water oxidation activity of the Fe2O3 photoanode with a 60 mV cathodically shifted onset potential. The C/Co3O4-Fe2O3 photoanode exhibits a photocurrent density of 1.48 mA cm−2 at 1.23 V (vs. reversible hydrogen electrode), 78 % higher than that of the bare Fe2O3 photoanode. The slow reaction process on the single CoIII-OH site of the Co3O4 cocatalyst, oxidizing H2O to H2O2 with two photogenerated holes, could be accelerated by the timely H2O2 oxidation to O2 catalyzed on CDots.
Co-reporter:Dr. Peng Zhang; Tuo Wang;Xiaoxia Chang; Lei Zhang ; Jinlong Gong
Angewandte Chemie International Edition 2016 Volume 55( Issue 19) pp:
Publication Date(Web):
DOI:10.1002/anie.201603126
Co-reporter:Xiaoxia Chang;Dr. Tuo Wang;Dr. Peng Zhang;Yijia Wei;Jiubing Zhao ;Dr. Jinlong Gong
Angewandte Chemie International Edition 2016 Volume 55( Issue 31) pp:8840-8845
Publication Date(Web):
DOI:10.1002/anie.201602973
Abstract
Photocatalytic reduction of CO2 to produce fuels is a promising way to reduce CO2 emission and address the energy crisis. However, the H2 evolution reaction competes with CO2 photoreduction, which would lower the overall selectivity for carbonaceous products. Cu2O has emerged as a promising material for suppressing the H2 evolution. However, it suffers from poor stability, which is commonly regarded as the result of the electron-induced reduction of Cu2O. This paper describes a simple strategy using Cu2O as a dark cathode and TiO2 as a photoanode to achieve stable aqueous CO2 reduction with a high Faradaic efficiency of 87.4 % and a selectivity of 92.6 % for carbonaceous products. We have shown that the photogenerated holes, instead of the electrons, primarily account for the instability of Cu2O. Therefore, Cu2O was used as a dark cathode to minimize the adverse effects of holes, by which an improved stability was achieved compared to the Cu2O photocathode under illumination. Additionally, direct exposure of the Cu2O surface to the electrolyte was identified as a critical factor for the high selectivity for carbonaceous products.
Co-reporter:Xiaoxia Chang;Dr. Tuo Wang;Dr. Peng Zhang;Yijia Wei;Jiubing Zhao ;Dr. Jinlong Gong
Angewandte Chemie International Edition 2016 Volume 55( Issue 31) pp:
Publication Date(Web):
DOI:10.1002/anie.201683161
Co-reporter:Dr. Peng Zhang; Tuo Wang;Xiaoxia Chang; Lei Zhang ; Jinlong Gong
Angewandte Chemie 2016 Volume 128( Issue 19) pp:5945-5949
Publication Date(Web):
DOI:10.1002/ange.201600918
Abstract
Cocatalysis plays an important role in enhancing the activity of semiconductor photocatalysts for solar water splitting. Compared to a single cocatalyst configuration, a cocatalytic system consisting of multiple components with different functions may realize outstanding enhancement through their interactions, yet limited research has been reported. Herein we describe the synergistic cocatalytic effect between carbon nanodots (CDots) and Co3O4, which promotes the photoelectrochemical water oxidation activity of the Fe2O3 photoanode with a 60 mV cathodically shifted onset potential. The C/Co3O4-Fe2O3 photoanode exhibits a photocurrent density of 1.48 mA cm−2 at 1.23 V (vs. reversible hydrogen electrode), 78 % higher than that of the bare Fe2O3 photoanode. The slow reaction process on the single CoIII-OH site of the Co3O4 cocatalyst, oxidizing H2O to H2O2 with two photogenerated holes, could be accelerated by the timely H2O2 oxidation to O2 catalyzed on CDots.
Co-reporter:Xiaoxia Chang;Dr. Tuo Wang;Dr. Peng Zhang;Yijia Wei;Jiubing Zhao ;Dr. Jinlong Gong
Angewandte Chemie 2016 Volume 128( Issue 31) pp:8986-8991
Publication Date(Web):
DOI:10.1002/ange.201602973
Abstract
Photocatalytic reduction of CO2 to produce fuels is a promising way to reduce CO2 emission and address the energy crisis. However, the H2 evolution reaction competes with CO2 photoreduction, which would lower the overall selectivity for carbonaceous products. Cu2O has emerged as a promising material for suppressing the H2 evolution. However, it suffers from poor stability, which is commonly regarded as the result of the electron-induced reduction of Cu2O. This paper describes a simple strategy using Cu2O as a dark cathode and TiO2 as a photoanode to achieve stable aqueous CO2 reduction with a high Faradaic efficiency of 87.4 % and a selectivity of 92.6 % for carbonaceous products. We have shown that the photogenerated holes, instead of the electrons, primarily account for the instability of Cu2O. Therefore, Cu2O was used as a dark cathode to minimize the adverse effects of holes, by which an improved stability was achieved compared to the Cu2O photocathode under illumination. Additionally, direct exposure of the Cu2O surface to the electrolyte was identified as a critical factor for the high selectivity for carbonaceous products.
Co-reporter:Xiaoxia Chang;Dr. Tuo Wang;Dr. Peng Zhang;Yijia Wei;Jiubing Zhao ;Dr. Jinlong Gong
Angewandte Chemie 2016 Volume 128( Issue 31) pp:
Publication Date(Web):
DOI:10.1002/ange.201683161
Co-reporter:Dr. Peng Zhang; Tuo Wang;Xiaoxia Chang; Lei Zhang ; Jinlong Gong
Angewandte Chemie 2016 Volume 128( Issue 19) pp:
Publication Date(Web):
DOI:10.1002/ange.201603126
Co-reporter:Junqing Yan;Tuo Wang;Guangjun Wu;Weili Dai;Naijia Guan;Long Li
Advanced Materials 2015 Volume 27( Issue 9) pp:1580-1586
Publication Date(Web):
DOI:10.1002/adma.201404792
Co-reporter:Peng Zhang;Tuo Wang
Advanced Materials 2015 Volume 27( Issue 36) pp:5328-5342
Publication Date(Web):
DOI:10.1002/adma.201500888
H2 generation by solar water splitting is one of the most promising solutions to meet the increasing energy demands of the fast developing society. However, the efficiency of solar-water-splitting systems is still too low for practical applications, which requires further enhancement via different strategies such as doping, construction of heterojunctions, morphology control, and optimization of the crystal structure. Recently, integration of plasmonic metals to semiconductor photocatalysts has been proved to be an effective way to improve their photocatalytic activities. Thus, in-depth understanding of the enhancement mechanisms is of great importance for better utilization of the plasmonic effect. This review describes the relevant mechanisms from three aspects, including: i) light absorption and scattering; ii) hot-electron injection and iii) plasmon-induced resonance energy transfer (PIRET). Perspectives are also proposed to trigger further innovative thinking on plasmonic-enhanced solar water splitting.
Co-reporter:Xiaoxia Chang; Tuo Wang; Peng Zhang; Jijie Zhang; Ang Li
Journal of the American Chemical Society 2015 Volume 137(Issue 26) pp:8356-8359
Publication Date(Web):June 19, 2015
DOI:10.1021/jacs.5b04186
Surface reaction kinetics and bulk charge separation are both critical to the efficiency of solar water splitting. In addition to the well-documented surface catalytic effect, the promotion of bulk charge separation upon loading of cocatalysts has rarely been reported. This paper describes the synergetic enhancement of surface reaction kinetics and bulk charge separation by introducing discrete nanoisland p-type Co3O4 cocatalysts onto n-type BiVO4, forming a p–n Co3O4/BiVO4 heterojunction with an internal electric field to facilitate charge transport. Being highly dispersed on the surface of photoanodes, the nanoisland cocatalysts could suppress the formation of recombination centers at the photoanode/cocatalyst interface. This cocatalyst-loading method achieved a charge separation efficiency of up to 77% in the bulk and 47% on the surface of catalysts. An AM 1.5G photocurrent of 2.71 mA/cm2 at 1.23 V versus the reversible hydrogen electrode for water oxidation was obtained, which is the highest photocurrent yet reported for Co-catalyzed undoped BiVO4 photoanodes, with a photoconversion efficiency of 0.659%.
Co-reporter:Hao Tian, Xinyu Li, Liang Zeng, and Jinlong Gong
ACS Catalysis 2015 Volume 5(Issue 8) pp:4959
Publication Date(Web):July 14, 2015
DOI:10.1021/acscatal.5b01221
Inexpensive group VIII metal (i.e., Fe, Co, and Ni)-based solid catalysts have been widely used in various energy transformation processes such as Fischer–Tropsch (F–T) synthesis, reforming, and water–gas shift reactions. The emerging encapsulation strategy, which represents active metal species that are coated by a protective shell or matrix, has been demonstrated as a powerful means to promote the catalytic performance (i.e., activity, stability, and selectivity) of Fe-, Co-, and Ni-based catalysts due to synergic effects from the well-defined structures. This review describes recent progress on the design and synthesis of encapsulated group VIII base-metal nanomaterials developed for energy and environmental catalysis including syngas conversion, CO2 dry reforming, steam reforming, methane conversion, and NH3 decomposition. We start with an introduction of the catalysts with different encapsulating structures (e.g., core@shell, yolk@shell, core@tube, mesoporous structures, and lamellar structures). Then, the synthetic methods of Fe-, Co-, and Ni-based catalysts with encapsulated structures are described in detail. The functions of encapsulation structures in catalysis, including protecting metal nanoparticles (NPs) from sintering, promoting the activity due to the confinement effect, and intensifying reaction processes in the form of multifunctional catalysts, are discussed, respectively. Our perspectives regarding the challenges and opportunities for future research in the field are also provided.Keywords: antisintering; catalyst design; cobalt; confinement effect; encapsulation structure; group VIII base metal; iron; multifunctional catalysts; nickel
Co-reporter:Zhi-Jian Zhao, Cheng-chau Chiu and Jinlong Gong
Chemical Science 2015 vol. 6(Issue 8) pp:4403-4425
Publication Date(Web):12 Jun 2015
DOI:10.1039/C5SC01227A
Due to the depletion of petroleum and the recent shale gas revolution, the dropping of the price for light alkanes makes alkanes an attractive feedstock for the production of light alkenes and other valuable chemicals. Understanding the mechanism for the activation of C–H bonds in hydrocarbons provides fundamental insights into this process and a guideline for the optimization of catalysts used for the processing of light alkanes. In the last two decades, density functional theory (DFT) has become a powerful tool to explore elementary steps and mechanisms of many heterogeneously catalyzed processes at the atomic scale. This review describes recent progress on computational understanding of heterogeneous catalytic dehydrogenation reactions of light alkanes. We start with a short description on basic concepts and principles of DFT as well as its application in heterogeneous catalysis. The activation of C–H bonds over transition metal and alloy surfaces are then discussed in detail, followed by C–H activation over oxides, zeolites and catalysts with single atoms as active sites. The origins of coking formation are also discussed followed by a perspective on directions of future research.
Co-reporter:Feng Jiang, Liang Zeng, Shuirong Li, Gang Liu, Shengping Wang, and Jinlong Gong
ACS Catalysis 2015 Volume 5(Issue 1) pp:438
Publication Date(Web):December 8, 2014
DOI:10.1021/cs501279v
This paper describes an investigation on understanding catalytic consequences of Pt nanoparticles supported on a TiO2–Al2O3 binary oxide for propane dehydrogenation (PDH). The TiO2–Al2O3 supports were synthesized by a sol–gel method, and the Pt/TiO2–Al2O3 catalysts were prepared by an incipient wetness impregnation method. Both as-prepared and post-experiment catalysts were characterized employing N2 adsorption–desorption, X-ray diffraction, Raman spectra, H2–O2 titration, temperature-programmed desorption, thermogravimetric analysis, temperature-programmed oxidation, transmission electron microscopy, and Fourier-transform infrared spectra of chemisorbed CO. We have shown that TiO2 is highly dispersed on Al2O3, and the addition of appropriate amount of TiO2 improves propylene selectivity and catalytic stability, which is ascribed to the electron transfer from partially reduced TiOx (x < 2) to Pt atoms. The increased electron density of Pt could reduce the adsorption of propylene and facilitate the migration of coke precursors from the metal surface to the support. The addition of TiO2, however, also increases the amount of strong acid centers on the supports and the excessive TiO2 addition might lead to a significant amount of coke formation. The electron transfer effect and the acid sites effect of TiO2 addition exert an opposite influence on catalytic performance. The trade-off between the electron transfer effect and the acid sites effect is studied by varying the amount of TiO2 loading. An optimal loading content of TiO2 is 10 wt %, which results in a higher propylene selectivity and a better stability.Keywords: C3H6 desorption; coke (precursors) migration; electron transfer; propane dehydrogenation; TiO2−Al2O3
Co-reporter:Peng Zhang, Tuo Wang, Jijie Zhang, Xiaoxia Chang and Jinlong Gong
Nanoscale 2015 vol. 7(Issue 31) pp:13153-13158
Publication Date(Web):19 May 2015
DOI:10.1039/C5NR03013G
This paper describes an approach to synthesize a tightly adhered Ta3N5 nanotube array (NTA) photoanode with enhanced electron conductivity between the Ta3N5 layer and the substrate via a two-step anodization method. The obtained tightly adhered Ta3N5 NTA photoanode exhibits excellent photoelectrochemical properties with an optimal photocurrent up to 5.3 mA cm−2 at 1.6 V vs. the reversible hydrogen electrode. This approach provides an effective strategy to address the adhesion issue of one dimensional semiconductor photoanodes.
Co-reporter:Tuo Wang, Rui Lv, Peng Zhang, Changjiang Li and Jinlong Gong
Nanoscale 2015 vol. 7(Issue 1) pp:77-81
Publication Date(Web):24 Jul 2014
DOI:10.1039/C4NR03735A
This paper describes the synthesis of Au nanoparticle sensitized ZnO nanopencil arrays on F-doped SnO2 substrates by an aqueous chemical growth and subsequent photoreduction method. The Au–ZnO nanopencil arrays yield a photocurrent of ∼1.5 mA cm−2 at 1 V versus Ag/AgCl. The enhanced photocurrent is attributed to the surface plasmon resonance effect of Au nanoparticles and the prolonged lifetime of the photo-generated electron–hole pairs. The improved stability of ZnO is due to the plasmon resonance energy transfer process enabled by the Au nanoparticles, which enhances the electric field intensity in a small, well-defined location of the ZnO semiconductor.
Co-reporter:Tuo Wang, Xiang Yuan, Shuirong Li, Liang Zeng and Jinlong Gong
Nanoscale 2015 vol. 7(Issue 17) pp:7593-7602
Publication Date(Web):29 Jan 2015
DOI:10.1039/C5NR00246J
Tuning the interfacial perimeter and structure is crucial to understanding the origin of catalytic performance. This paper describes the design, characterization, and application of CeO2 modified Au@SBA-15 (Au–CeO2@SBA-15) catalysts in selective oxidation of benzyl alcohol. The reaction results showed that Au–CeO2@SBA-15 catalysts exhibited higher catalytic activity compared with Au@SBA-15 and Au/CeO2 catalysts under identical conditions along with the high selectivity towards benzaldehyde (>99%). The turnover frequency of benzyl alcohol over the Au–100CeO2@SBA-15 catalyst is about nine-fold and four-fold higher than those of Au@SBA-15 and Au/CeO2 catalysts, respectively. The supported catalysts were characterized by N2 adsorption–desorption, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, transmission electron microscopy, high-angle annular dark-field scanning transmission electron microscopy, scanning transmission electron microscopy-energy dispersive spectrometry, and X-ray photoelectron spectroscopy. It was found that the Au and small CeO2 nanoparticles (∼5 nm) were homogeneously mixed in the channels of SBA-15, which led to an increase in the interfacial area between Au and CeO2 and consequently a better catalytic performance of Au–CeO2@SBA-15 catalysts for the selective oxidation of benzyl alcohol to benzaldehyde compared with that of Au/CeO2. The prevention of agglomeration and leaching of Au nanoparticles by restricting them inside the mesopores of SBA-15 was conducive to the stable existence of large quantities of Au–CeO2 interface, which leads to high stability of the Au–CeO2@SBA-15 catalyst.
Co-reporter:Chengcheng Li, Tuo Wang, Zhibin Luo, Dong Zhang and Jinlong Gong
Chemical Communications 2015 vol. 51(Issue 34) pp:7290-7293
Publication Date(Web):02 Mar 2015
DOI:10.1039/C5CC01015B
This communication describes a highly stable ZnO/Ta2O5 photoanode with Ta2O5 deposited by atomic layer deposition. The ultrathin Ta2O5 protective layer prevents corrosion of ZnO and reduces surface carrier recombination, leading to a nearly two-fold increase of photo-conversion efficiency. The transparency of Ta2O5 to sunlight is identified as the main reason for the excellent stability of the photoelectrode for 5 hours.
Co-reporter:Tuo Wang;Yali Meng;Liang Zeng
Science Bulletin 2015 Volume 60( Issue 11) pp:1009-1018
Publication Date(Web):2015 June
DOI:10.1007/s11434-015-0782-3
This paper describes the effect of the preparation method of binary oxide supports (TiO2–Al2O3) on catalytic performance of V2O5/TiO2–Al2O3 catalysts for methanol selective oxidation to dimethoxymethane (DMM). The TiO2–Al2O3 supports are synthesized by a number of methods including mechanical mixing, ball milling, precipitation, co-precipitation, and sol–gel method, which is followed by incipient wetness impregnation to produce V2O5/TiO2–Al2O3 catalysts. Among these samples, the V2O5/TiO2–Al2O3 catalyst prepared by the sol–gel method has the best catalytic performance with a maximum methanol conversion of 48.9 % and a high DMM selectivity of 89.9 % at 393 K, showing superior performance than V2O5/TiO2 and V2O5/Al2O3. The excellent catalytic performance of V2O5/TiO2–Al2O3 is attributed to the effective interaction between the active component and the mixed support. Such interaction changes the chemical states of supported active V components, produces an increased amount of V4+ species, and facilitates the electron transfer between support and active component. Additionally, the incorporation of titanium cation into the alumina structure could also help produce an appropriate amount of acidic sites, which increases the DMM selectivity. The coordinated environment of the dispersed vanadia on TiO2–Al2O3 mixed support improves the catalytic efficiency on methanol oxidation to DMM.本文介绍了甲醇选择性氧化制备二甲氧基甲烷(DMM)过程中, 二元TiO2-Al2O3氧化物载体的制备方法对V2O5/TiO2-Al2O3催化剂性能的影响. 考察的制备方法包括机械混合、球磨、沉淀、共同沉淀、溶胶凝胶法, 随后通过等体积浸渍制备出V2O5/TiO2-Al2O3催化剂. 其中, 溶胶凝胶法制得的V2O5/TiO2-Al2O3催化剂具有最高的催化活性, 在393 K下表现出48.9 %的转化率和89 %的DMM选择性, 优于V2O5/TiO2, V2O5/Al2O3催化剂. V2O5/TiO2-Al2O3优良的性能是由于催化活性组分与混合型载体之间有效的相互作用. 这种相互作用改变了活性V组分的化学态, 生成了更多的V4+物种, 促进了载体与活性组分之间的电子转移. 此外,Ti离子可通过嵌入Al2O3晶体来生成含量适宜的酸性位, 进而提高DMM的选择性.
Co-reporter:Jijie Zhang, Peng Zhang, Tuo Wang, Jinlong Gong
Nano Energy 2015 Volume 11() pp:189-195
Publication Date(Web):January 2015
DOI:10.1016/j.nanoen.2014.10.021
•γ-monoclinic WO3 nanomultilayers were synthesized through a facile solvothermal method.•An excellent photocurrent of 1.62 mA cm−2 at 1.25 V (vs. Ag/AgCl) under AM 1.5 G irradiation was observed.•The controllable exposure of highly reactive (002) facets was demonstrated.This article describes the synthesis of γ-monoclinic WO3 nanomultilayers with highly reactive (002) facets exposed through a facile solvothermal method using ethylene glycol as the solvent. The multilayered WO3 exhibits a unique structure where a larger backbone nanosheet is sandwiched by smaller nanosheets from both sides. The obtained electrode showed a photocurrent density of 1.62 mA cm−2 at 1.25 V versus Ag/AgCl (pH 6.8) and a photoconversion efficiency of 0.154% under AM 1.5 G owing to the preferentially exposed highly active (002) facets.This article describes the synthesis of γ-monoclinic WO3 nanomultilayers with highly reactive (002) facets exposed through a facile solvothermal method using ethylene glycol as the solvent. The multilayered WO3 exhibits a unique structure where a larger backbone nanosheet is sandwiched by smaller nanosheets from both sides. The obtained electrode showed a photocurrent density of 1.62 mA cm−2 at 1.25 V versus Ag/AgCl (pH 6.8) and a photoconversion efficiency of 0.154% under AM 1.5 G owing to the preferentially exposed highly active (002) facets.
Co-reporter:Peng Zhang, Ang Li, Jinlong Gong
Particuology 2015 Volume 22() pp:13-23
Publication Date(Web):October 2015
DOI:10.1016/j.partic.2015.03.001
•Synthetic approaches of hollow spherical TiO2 nanoparticles were reviewed.•Their performances in DSSCs, photocatalysts and batteries were reviewed.•Perspectives on further improving their synthesis and characterization methods were drawn.Hollow spherical titanium dioxide (TiO2) nanoparticles possess unique properties toward energy and environmental applications, because of the intrinsic properties of TiO2 and benefits induced by their hollow structure. A detailed understanding of TiO2 hollow spheres will promote their use in sustainable energy and environmental applications. This perspective details current methods for synthesizing hollow spherical TiO2 nanoparticles, and their performance in dye-sensitized solar cells, photocatalysts, and batteries. This perspective will promote the design and innovative thinking on the application of hollow spherical metal oxide nanoparticles.
Co-reporter:Hao Tian;Shuirong Li;Liang Zeng;Hongyan Ma
Science China Materials 2015 Volume 58( Issue 1) pp:9-15
Publication Date(Web):2015 January
DOI:10.1007/s40843-014-0014-1
The high-temperature methanation of CO is an important reaction in the processes used to produce substitute natural gas, while the Ni-based catalysts prepared using the conventional impregnation method tend to deactivate under high-temperature reaction conditions. This paper describes the design and assembly of ordered mesoporous alumina (OMA) using highly disperse ∼5 nm nickel nanoparticles (Ni NPs), via a one-pot, evaporation-induced self-assembly (EISA) method. Small-angle X-ray diffraction (XRD), transmission electron microscope (TEM), and N2 adsorption and desorption results revealed that this catalytic material had highly ordered mesopores, which were retained even after long-term stability tests. The catalyst exhibited excellent sintering-resistant and anti-coking properties in high-temperature CO methanation reactions (60% CO conversion after 50 hours of accelerated deactivation at 700°C). The improved catalytic performance was attributed to the matrix of the OMA, which effectively improved the dispersion of the nickel particles, and prevented the Ni NPs from sintering, via a particle migration and coalescence mechanism. The Ni-OMA catalyst demonstrated here shows promise for high-temperature methanation.CO高温甲烷化反应是工业上生产合成天然气的重要反应, 采用传统的浸渍方法合成的镍基催化剂在高温的反应条件下容易发生烧结和积碳现象而导致失活. 本文以蒸发引导的自组装方法为原理, 通过“一锅法”设计并合成了有序介孔氧化铝负载高分散镍纳米颗粒(粒径在5 nm左右)的催化剂. 通过小角XRD、 TEM和N2物理吸附等表征验证了有序介孔结构的存在, 并且这种结构在长时间的高温稳定性测试后仍能保持. 该催化剂在CO高温甲烷化反应中表现出良 好的抗烧结、 抗积碳的性能. 载体氧化铝的有序介孔结构是这种催化剂性能提升的关键, 因为有序介孔结构有利于改善活性组分镍颗粒的分散情况, 同时纳米级的介孔孔道可以限制镍颗粒在高温下通过颗粒迁移和聚集而烧结长大.
Co-reporter:Assoc.Dr. Tuo Wang;Dr. Jinlong Gong
Angewandte Chemie International Edition 2015 Volume 54( Issue 37) pp:10718-10732
Publication Date(Web):
DOI:10.1002/anie.201503346
Abstract
Solar water splitting provides a clean and renewable approach to produce hydrogen energy. In recent years, single-crystal semiconductors such as Si and InP with narrow band gaps have demonstrated excellent performance to drive the half reactions of water splitting through visible light due to their suitable band gaps and low bulk recombination. This Minireview describes recent research advances that successfully overcome the primary obstacles in using these semiconductors as photoelectrodes, including photocorrosion, sluggish reaction kinetics, low photovoltage, and unfavorable planar substrate surface. Surface modification strategies, such as surface protection, cocatalyst loading, surface energetics tuning, and surface texturization are highlighted as the solutions.
Co-reporter:Assoc.Dr. Tuo Wang;Dr. Jinlong Gong
Angewandte Chemie International Edition 2015 Volume 54( Issue 37) pp:
Publication Date(Web):
DOI:10.1002/anie.201506277
Co-reporter:Assoc.Dr. Tuo Wang;Dr. Jinlong Gong
Angewandte Chemie 2015 Volume 127( Issue 37) pp:10866-10881
Publication Date(Web):
DOI:10.1002/ange.201503346
Abstract
Die Wasserspaltung mittels Sonnenenergie bietet einen sauberen und erneuerbaren Ansatz für die Produktion von Wasserstoff. Einkristalline Halbleiter mit kleinen Bandlücken und geringer Ladungsträgerrekombination, wie Si und InP, erweisen sich als sehr gut geeignet, die Halbreaktionen der Wasserspaltung – die Wasserstoff- (HER) und Sauerstoffentwicklung (OER) – unter Einwirkung von sichtbarem Licht zu fördern. Durch die Verwendung dieser Halbleiter als Photoelektroden konnte in jüngster Zeit eine Reihe von Problemen im Zusammenhang mit Photokorrosion, langsamen Reaktionskinetiken, niedrigen Photospannungen und ungünstigen planaren Substratoberflächen gelöst werden. Dieser Kurzaufsatz fasst den aktuellen Stand der Forschungen zusammen, mit Schwerpunkt auf Oberflächenmodifizierungsstrategien, wie z. B. Oberflächenschützung, Beladung mit Kokatalysatoren, Abstimmung der Oberflächenenergetiken und Oberflächentexturierung.
Co-reporter:Assoc.Dr. Tuo Wang;Dr. Jinlong Gong
Angewandte Chemie 2015 Volume 127( Issue 37) pp:
Publication Date(Web):
DOI:10.1002/ange.201506277
Co-reporter:Tuo Wang, Zhibin Luo, Chengcheng Li and Jinlong Gong
Chemical Society Reviews 2014 vol. 43(Issue 22) pp:7469-7484
Publication Date(Web):06 Feb 2014
DOI:10.1039/C3CS60370A
Photoelectrochemical (PEC) water splitting is an attractive approach to generate hydrogen as a clean chemical fuel from solar energy. But there remain many fundamental issues to be solved, including inadequate photon absorption, short carrier diffusion length, surface recombination, vulnerability to photo-corrosion, and unfavorable reaction kinetics. Owing to its self-limiting surface reaction mechanism, atomic layer deposition (ALD) is capable of depositing thin films in a highly controllable manner, which makes it an enabling technique to overcome some of the key challenges confronted by PEC water splitting. This tutorial review describes some unique and representative applications of ALD in fabricating high performance PEC electrodes with various nanostructures, including (i) coating conformal thin films on three-dimensional scaffolds to facilitate the separation and migration of photocarriers and enhance light trapping, as well as realizing controllable doping for bandgap engineering and forming homojunctions for carrier separation; (ii) achieving surface modification through deposition of anti-corrosion layers, surface state passivation layers, and surface catalytic layers; and (iii) identifying the main rate limiting steps with model electrodes with highly defined thickness, composition, and interfacial structure.
Co-reporter:Jinlong Gong and Rafael Luque
Chemical Society Reviews 2014 vol. 43(Issue 22) pp:7466-7468
Publication Date(Web):07 Oct 2014
DOI:10.1039/C4CS90084G
A graphical abstract is available for this content
Co-reporter:Shuirong Li and Jinlong Gong
Chemical Society Reviews 2014 vol. 43(Issue 21) pp:7245-7256
Publication Date(Web):03 Sep 2014
DOI:10.1039/C4CS00223G
Owing to the considerable publicity that has been given to petroleum related economic, environmental, and political problems, renewed attention has been focused on the development of highly efficient and stable catalytic materials for the production of chemical/fuel from renewable resources. Supported nickel nanoclusters are widely used for catalytic reforming reactions, which are key processes for generating synthetic gas and/or hydrogen. New challenges were brought out by the extension of feedstock from hydrocarbons to oxygenates derivable from biomass, which could minimize the environmental impact of carbonaceous fuels and allow a smooth transition from fossil fuels to a sustainable energy economy. This tutorial review describes the recent efforts made toward the development of nickel-based catalysts for the production of hydrogen from oxygenated hydrocarbons via steam reforming reactions. In general, three challenges facing the design of Ni catalysts should be addressed. Nickel nanoclusters are apt to sinter under catalytic reforming conditions of high temperatures and in the presence of steam. Severe carbon deposition could also be observed on the catalyst if the surface carbon species adsorbed on metal surface are not removed in time. Additionally, the production of hydrogen rich gas with a low concentration of CO is a challenge using nickel catalysts, which are not so active in the water gas shift reaction. Accordingly, three strategies were presented to address these challenges. First, the methodologies for the preparation of highly dispersed nickel catalysts with strong metal–support interaction were discussed. A second approach—the promotion in the mobility of the surface oxygen—is favored for the yield of desired products while promoting the removal of surface carbon deposition. Finally, the process intensification via the in situ absorption of CO2 could produce a hydrogen rich gas with low CO concentration. These approaches could also guide the design of other types of heterogeneous base-metal catalysts for high temperature processes including methanation, dry reforming, and hydrocarbon combustion.
Co-reporter:Peng Zhang, Jijie Zhang and Jinlong Gong
Chemical Society Reviews 2014 vol. 43(Issue 13) pp:4395-4422
Publication Date(Web):25 Mar 2014
DOI:10.1039/C3CS60438A
Solar energy utilization is one of the most promising solutions for the energy crises. Among all the possible means to make use of solar energy, solar water splitting is remarkable since it can accomplish the conversion of solar energy into chemical energy. The produced hydrogen is clean and sustainable which could be used in various areas. For the past decades, numerous efforts have been put into this research area with many important achievements. Improving the overall efficiency and stability of semiconductor photocatalysts are the research focuses for the solar water splitting. Tantalum-based semiconductors, including tantalum oxide, tantalate and tantalum (oxy)nitride, are among the most important photocatalysts. Tantalum oxide has the band gap energy that is suitable for the overall solar water splitting. The more negative conduction band minimum of tantalum oxide provides photogenerated electrons with higher potential for the hydrogen generation reaction. Tantalates, with tunable compositions, show high activities owning to their layered perovskite structure. (Oxy)nitrides, especially TaON and Ta3N5, have small band gaps to respond to visible-light, whereas they can still realize overall solar water splitting with the proper positions of conduction band minimum and valence band maximum. This review describes recent progress regarding the improvement of photocatalytic activities of tantalum-based semiconductors. Basic concepts and principles of solar water splitting will be discussed in the introduction section, followed by the three main categories regarding to the different types of tantalum-based semiconductors. In each category, synthetic methodologies, influencing factors on the photocatalytic activities, strategies to enhance the efficiencies of photocatalysts and morphology control of tantalum-based materials will be discussed in detail. Future directions to further explore the research area of tantalum-based semiconductors for solar water splitting are also discussed.
Co-reporter:Hairong Yue, Xinbin Ma, and Jinlong Gong
Accounts of Chemical Research 2014 Volume 47(Issue 5) pp:1483
Publication Date(Web):February 26, 2014
DOI:10.1021/ar4002697
Ethanol is an attractive end product and a versatile feedstock because a widespread market exists for its commercial use as a fuel additive or a potential substitute for gasoline. Currently, ethanol is produced primarily by fermentation of biomass-derived sugars, particularly those containing six carbons, but coproducts 5-carbon sugars and lignin remain unusable. Another major process for commercial production of ethanol is hydration of ethylene over solid acidic catalysts, yet not sustainable considering the depletion of fossil fuels. Catalytic conversion of synthetic gas (CO + H2) could produce ethanol in large quantities. However, the direct catalytic conversion of synthetic gas to ethanol remains challenging, and no commercial process exists as of today although the research has been ongoing for the past 90 years, since such the process suffers from low yield and poor selectivity due to slow kinetics of the initial C–C bond formation and fast chain growth of the C2 intermediates.This Account describes recent developments in an alternative approach for the synthesis of ethanol via synthetic gas. This process is an integrated technology consisting of the coupling of CO with methanol to form dimethyl oxalate and the subsequent hydrogenation to yield ethanol. The byproduct of the second step (methanol) can be separated and used in circulation as the feedstock for the coupling step. The coupling reaction of carbon monoxide for producing dimethyl oxalate takes place under moderate reaction conditions with high selectivity (∼95%), which ideally leads to a self-closing, nonwaste, catalytic cycling process. This Account also summarizes the progress on the development of copper-based catalysts for the hydrogenation reaction with remarkable efficiencies and stability. The unique lamellar structure and the cooperative effect between surface Cu0 and Cu+ species are responsible for the activity of the catalyst with high yield of ethanol (∼91%). The understanding of nature of valence states of Cu could also guide the rational design of Cu-based catalysts for other similar reactions, particularly for hydrogenation catalytic systems. In addition, by regulating the reaction condition and the surface structure of the catalysts, the products in the hydrogenation steps, such as ethanol, methyl glycolate, and ethylene glycol, could be tuned efficiently. This synthetic approach enables a more sustainable ethanol, methyl glycolate, and ethylene glycol synthesis in industry and greatly reduces the dependence on petroleum resources and the emission of the greenhouse gas.
Co-reporter:Zhiping Han, Shuirong Li, Feng Jiang, Tuo Wang, Xinbin Ma and Jinlong Gong
Nanoscale 2014 vol. 6(Issue 17) pp:10000-10008
Publication Date(Web):05 May 2014
DOI:10.1039/C4NR02143F
This paper describes an investigation of the promotional effect of Cu on the catalytic performance of Pt/Al2O3 catalysts for propane dehydrogenation. We have shown that Pt/Al2O3 catalysts possess higher propylene selectivity and lower deactivation rate as well as enhanced anti-coking ability upon Cu addition. The optimized loading content of Cu is 0.5 wt%, which increases the propylene selectivity to 90.8% with a propylene yield of 36.5%. The origin of the enhanced catalytic performance and anti-coking ability of the Pt–Cu/Al2O3 catalyst is ascribed to the intimate interaction between Pt and Cu, which is confirmed by the change of particle morphology and atomic electronic environment of the catalyst. The Pt–Cu interaction inhibits propylene adsorption and elevates the energy barrier of C–C bond rupture. The inhibited propylene adsorption diminishes the possibility of coke formation and suppresses the cracking reaction towards the formation of lighter hydrocarbons on Pt–Cu/Al2O3, while a higher energy barrier for C–C bond cleavage suppresses the methane formation.
Co-reporter:Manh Huy Do, Tuo Wang, Dang-guo Cheng, Fengqiu Chen, Xiaoli Zhan and Jinlong Gong
Journal of Materials Chemistry A 2014 vol. 2(Issue 35) pp:14360-14370
Publication Date(Web):12 Jun 2014
DOI:10.1039/C4TA01737D
Understanding of the crystal growth mechanism of zeolites is essential for rational design of zeolite materials with desired physical and chemical properties, but still remains elusive. This paper describes experimental findings of zeolite crystal evolution from sodium-rich hydrogels, revealing that the zeolite nucleation occurs at the equilibrated gel phase of the condensed primary aggregates precipitated from the dissolved (alumino)silicate species. The nuclei produced from the nucleation could be diffused into the liquid–solid interface of the equilibrated gel phase and the liquid phase. The zeolite growth therefore occurs through a synergistic mechanism of two growth processes: a solution-mediated process and a solid-state transformation. In the liquid phase and the liquid–gel (equilibrated gel) interface, the oriented aggregation governs the zeolite growth in early stages. The major driving force for the aggregation is the electrostatic force between the positively charged active Na+ and the negative charges of the (TO−) groups on the surface of the nuclei and growing nanocrystals. In the last few steps the crystal growth by the coalescence and the Ostwald rule becomes predominant.
Co-reporter:Shengping Wang, Changjiang Li, Tuo Wang, Peng Zhang, Ang Li and Jinlong Gong
Journal of Materials Chemistry A 2014 vol. 2(Issue 9) pp:2885-2890
Publication Date(Web):2013/12/04
DOI:10.1039/C3TA14576J
This paper describes a facile and generally feasible method to synthesize nanotube-type graphitic carbon nitride (g-C3N4) by directly heating melamine packed in an appropriate compact degree which plays a crucial role in the formation process of g-C3N4. This approach has several advantages: (i) no templates or extra organics are involved; (ii) high industrial feasibility; (iii) low cost; and (iv) general applicability. The as-synthesized g-C3N4 samples show intense fluorescence with a photoluminescent (PL) peak at 460 nm indicating their potential applications as a blue light fluorescence material. They also exhibit excellent visible-light photocatalytic activity compared to a reference P25 photocatalyst. The method reported may open up new opportunities for further studies as well as practical applications of g-C3N4 nanotubes in fields such as light-emitting devices, gas storage and photocatalysis.
Co-reporter:Tuo Wang, Changjiang Li, Junyi Ji, Yijia Wei, Peng Zhang, Shengping Wang, Xiaobin Fan, and Jinlong Gong
ACS Sustainable Chemistry & Engineering 2014 Volume 2(Issue 10) pp:2253
Publication Date(Web):August 21, 2014
DOI:10.1021/sc5004665
This paper describes the construction of reduced graphene oxide (rGO)/BiVO4 composites with maximized interfacial coupling and their application as visible light photocatalysts. Thin rGO sheets (<5 nm) could completely cover BiVO4 polyhedrons with highly active (040) facets exposed through an evaporation-induced self-assembly process. In addition to the increased surface adsorption effect of rGO, a considerable enhancement of the photoactivity of BiVO4 has been demonstrated through the degradation of methylene blue upon the covering of rGO. The improved photocatalytic activity is attributed to the formation of well-defined rGO/BiVO4 interfaces, which greatly enhances the charge separation efficiency.Keywords: BiVO4; Charge separation; Interface; Photocatalytic degradation; Reduced graphene oxide (rGO); Visible light photocatalysis
Co-reporter:Rui Lv, Tuo Wang, Fengli Su, Peng Zhang, Changjiang Li, Jinlong Gong
Nano Energy 2014 Volume 7() pp:143-150
Publication Date(Web):July 2014
DOI:10.1016/j.nanoen.2014.04.020
•ZnO nanopencil arrays on FTO substrates was synthesized by an aqueous chemical method.•Oxygen vacancies in these arrays enhance the charge transportation.•A high photocurrent of ~1.3 mA/cm2 at 1 V versus Ag/AgCl was observed.This paper describes the downward growth of ZnO nanopencil arrays on F-doped SnO2 glass substrates by an aqueous chemical method. The ZnO nanopencil arrays have a unique structure with an abrupt shrinkage in diameter between the tip and the pencil-holder. The ZnO nanopencil arrays yield an elevated photocurrent of ~1.3 mA/cm2 at 1 V versus Ag/AgCl under 100 mW/cm2 illumination (AM 1.5), which is almost 2 times larger than that of the ZnO nanorod arrays. The enhanced photocurrent is attributed to an increased density of oxygen vacancies that could enhance the charge transportation by reducing the electron–hole recombination.This paper describes the downward growth of ZnO nanopencil arrays on F-doped SnO2 glass substrates via an aqueous chemical method for highly efficient photoelectrochemical water splitting.
Co-reporter:Fengli Su, Tuo Wang, Rui Lv, Jijie Zhang, Peng Zhang, Jianwei Lu and Jinlong Gong
Nanoscale 2013 vol. 5(Issue 19) pp:9001-9009
Publication Date(Web):01 Jul 2013
DOI:10.1039/C3NR02766J
This paper describes the synthesis of TiO2 branched nanorod arrays (TiO2 BNRs) with plasmonic Au nanoparticles attached on the surface. Such Au/TiO2 BNR composites exhibit high photocatalytic activity in photoelectrochemical (PEC) water splitting. The unique structure of Au/TiO2 BNRs shows enhanced activity with a photocurrent of 0.125 mA cm−2 under visible light (≥420 nm) and 2.32 ± 0.1 mA cm−2 under AM 1.5 G illumination (100 mW cm−2). The obtained photocurrent is comparable to the highest value ever reported. Furthermore, the Au/TiO2 BNRs achieve the highest efficiency of ∼1.27% at a low bias of 0.50 V vs. RHE, indicating elevated charge separation and transportation efficiencies. The high PEC performance is mainly due to the plasmonic effect of Au nanoparticles, which enhances the visible light absorption, together with the large surface area, efficient charge separation and high carrier mobility of the TiO2 BNRs. The carrier density of Au/TiO2 BNRs is nearly 6 times higher than the pristine TiO2 BNRs as calculated by the Mott–Schottky plot. Based on the analysis by UV-Vis spectroscopy, electrochemical impedance spectroscopy, and photoluminescence, a mechanism was proposed to explain the high activity of Au/TiO2 BNRs in PEC water splitting. The capability of synthesizing highly visible light active Au/TiO2 BNR based photocatalysts is useful for solar conversion applications, such as PEC water splitting, dye-sensitized solar cells and photovoltaic devices.
Co-reporter:Shengping Wang, Lifang Zhao, Wei Wang, Yujun Zhao, Guanglin Zhang, Xinbin Ma and Jinlong Gong
Nanoscale 2013 vol. 5(Issue 12) pp:5582-5588
Publication Date(Web):22 Apr 2013
DOI:10.1039/C3NR00831B
This paper describes the synthesis of ceria catalysts with octahedron, nanorod, nanocube and spindle-like morphologies via a template-free hydrothermal method. The surface morphologies, crystal plane and physical-chemical structures were investigated via field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and temperature-programmed desorption of ammonia and carbon dioxide (NH3-TPD and CO2-TPD). The catalytic performance over these ceria catalysts with different exposed planes were tested for dimethyl carbonate (DMC) synthesis from CO2 and methanol. The results showed that the spindle-like CeO2 showed the highest DMC yields, followed by nano-rods, nano-cubes and nano-octahedrons. A synergism among the exposed (111) plane, defect sites, and acid-basic sites was proposed to be crucial to obtaining the high reactivity of DMC formation.
Co-reporter:Shuirong Li, Chengxi Zhang, Zhiqi Huang, Gaowei Wu and Jinlong Gong
Chemical Communications 2013 vol. 49(Issue 39) pp:4226-4228
Publication Date(Web):24 Oct 2012
DOI:10.1039/C2CC37109J
This communication describes the synthesis of a nanocomposite Ni@ZrO2 catalyst with enhanced metal–support interaction by introducing metal nanoparticles into the framework of the oxide support. The catalyst shows high catalytic activity and stability for hydrogen production via steam reforming of ethanol.
Co-reporter:Chengxi Zhang, Wancheng Zhu, Shuirong Li, Gaowei Wu, Xinbin Ma, Xun Wang and Jinlong Gong
Chemical Communications 2013 vol. 49(Issue 82) pp:9383-9385
Publication Date(Web):22 Jul 2013
DOI:10.1039/C3CC43895C
This communication describes the design and synthesis of anti-sintering and -coke nickel phyllosilicate (PS) nanotubes (Ni/PSn) for hydrogen production via reforming reactions. The introduction of nickel particles in PS nanotubes could effectively maintain the Ni size and increase the resistance of metal particles for carbon deposition.
Co-reporter:Jianwei Lu, Peng Zhang, Ang Li, Fengli Su, Tuo Wang, Yuan Liu and Jinlong Gong
Chemical Communications 2013 vol. 49(Issue 52) pp:5817-5819
Publication Date(Web):08 Apr 2013
DOI:10.1039/C3CC42029A
This communication describes a method for facile synthesis of mesoporous anatase TiO2 nanocup crystals. The novel cuplike morphology of TiO2 decorated with gold (Au–TiO2) yields remarkably high photocatalytic activity for degradation of methylene blue under visible light irradiation.
Co-reporter:Chengxi Zhang, Shuirong Li, Tuo Wang, Gaowei Wu, Xinbin Ma and Jinlong Gong
Chemical Communications 2013 vol. 49(Issue 90) pp:10647-10649
Publication Date(Web):20 Sep 2013
DOI:10.1039/C3CC45957H
This communication describes the synthesis of Pt@CeO2 core–shell catalysts for the application of highly efficient CO oxidation, where the 50% CO conversion temperature is lower than 200 °C. Pt@CeO2 is thermally stable as no deactivation occurs during the 70 h reaction, and the morphology is unchanged even after 700 °C thermal treatment.
Co-reporter:Peng Zhang, Jie He, Xinbin Ma, Jinlong Gong and Zhihong Nie
Chemical Communications 2013 vol. 49(Issue 10) pp:987-989
Publication Date(Web):12 Dec 2012
DOI:10.1039/C2CC37713F
This communication describes a facile method for the synthesis of conical-shaped Au nanoparticles with a hollow cavity by combining interfacial reaction and ultrasonic cavitation. The Au nanocones showed an enhancement factor of 7.7 × 108 in surface enhanced Raman scattering (SERS) detection.
Co-reporter:Chengxi Zhang, Hairong Yue, Zhiqi Huang, Shuirong Li, Gaowei Wu, Xinbin Ma, and Jinlong Gong
ACS Sustainable Chemistry & Engineering 2013 Volume 1(Issue 1) pp:161
Publication Date(Web):December 4, 2012
DOI:10.1021/sc300081q
This paper describes the design of Ni/SiO2 catalysts obtained from a phyllosilicate precursor that possess high activity and stability for bioethanol steam reforming to sustainably produce hydrogen. Sintering of metal particles and carbon deposition are two major issues of nickel-based catalysts for reforming processes, particularly at high temperatures; strong metal–support interaction could be a possible solution. We have successfully synthesized Ni-containing phyllosilicates by an ammonia evaporation method. Temperature programmed reduction results indicate that the metal–support interaction of Ni/SiO2 catalyst prepared by ammonia evaporation method (Ni/SiO2P) is stronger due to the unique layered structure compared to that prepared by conventional impregnation (Ni/SiO2I). With the phyllosilicate precursor nickel particles highly disperse on the surface, remaining OH groups in the unreduced phyllosilicates promote nickel dispersion and carbon elimination. We also show that high dispersion of Ni and strong metal–support interaction of Ni/SiO2P significantly promote ethanol conversion and H2 production in ethanol steam reforming. Ni/SiO2P produces less carbon deposition compared to Ni/SiO2I; for the latter, a surface layer of Ni3C formed during the deactivation.Keywords: Ethanol steam reforming; Hydrogen production; Metal−support interaction; Ni/SiO2; Phyllosilicates
Co-reporter:Gaowei Wu, Chengxi Zhang, Shuirong Li, Zhiping Han, Tuo Wang, Xinbin Ma, and Jinlong Gong
ACS Sustainable Chemistry & Engineering 2013 Volume 1(Issue 8) pp:1052
Publication Date(Web):May 30, 2013
DOI:10.1021/sc400123f
This paper describes an investigation regarding the influence of Ni precursors on catalytic performances of Ni/Al2O3 catalysts in glycerol steam reforming. A series of Ni/Al2O3 is synthesized using four different precursors, nickel nitrate, nickel chloride, nickel acetate, and nickel acetylacetonate. Characterization results based on N2 adsorption–desorption, X-ray diffraction, H2 temperature-programmed reduction, H2 chemisorption, transmission electron microscopy, and thermogravimetric analysis show that reduction degrees of nickel, nickel dispersion, and particle sizes of Ni/Al2O3 catalysts are closely dependent on the anion size and nature of the nickel precursors. Ni/Al2O3 prepared by nickel acetate possesses the moderate Ni reduction degree, high Ni dispersion, and small nickel particle size, which possesses the highest H2 yield. Reaction parameters are also examined, and 550 °C and a steam-to-carbon ratio of 3 are optimized. Moreover, coke deposition, mainly graphite species, leads to the deactivation of Ni/Al2O3 catalysts in glycerol steam reforming. Nickel chloride-derived Ni/Al2O3 catalysts suffer from severe coke deposition and low reaction activity due to large Ni particle size, low Ni dispersion, and residual chloride.Keywords: Coke deposition; Glycerol steam reforming; Hydrogen production; Ni/Al2O3; Nickel precursor
Co-reporter:Jinlong Gong, Zhihong Nie and Xinbin Ma
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 29) pp:11985-11987
Publication Date(Web):27 Jun 2013
DOI:10.1039/C3CP90089D
A graphical abstract is available for this content
Co-reporter:Fengli Su, Jianwei Lu, Ye Tian, Xinbin Ma and Jinlong Gong
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 29) pp:12026-12032
Publication Date(Web):20 May 2013
DOI:10.1039/C3CP51291F
This paper describes the design, characterization, and utilization of branched TiO2 nanoarrays sensitized with CdS quantum dots as anodes for photoelectrochemical water splitting. The remarkable photocurrent density (∼4 mA cm−2 at a potential of 0 V versus Ag/AgCl) and high solar to hydrogen efficiency of the materials obtained were ascribed to the novel branched nanostructure and efficient electron transfer from CdS to TiO2.
Co-reporter:Jianwei Lu, Fengli Su, Zhiqi Huang, Chengxi Zhang, Yuan Liu, Xinbin Ma and Jinlong Gong
RSC Advances 2013 vol. 3(Issue 3) pp:720-724
Publication Date(Web):14 Nov 2012
DOI:10.1039/C2RA22713D
This paper describes the synthesis of TiO2 hollow spheres (HSs) modified via nitrogen doping and silver loading (Ag–N–TiO2) with particle diameters of ~100 nm. The specific surface area of the Ag–N–TiO2 was up to 147 m2 g−1 and this structure is stable upon high temperature treatment. Ag–N–TiO2 exhibited excellent photocatalytic activity for the degradation of dye compounds under visible light irradiation (≥410 nm) due to their larger surface area and controlled morphology compared with previously reported N-doped TiO2 fine particles (e.g. N–P25).
Co-reporter:Jinlong Gong
Chemical Reviews 2012 Volume 112(Issue 5) pp:2987
Publication Date(Web):April 27, 2011
DOI:10.1021/cr200041p
Co-reporter:Hairong Yue, Yujun Zhao, Xinbin Ma and Jinlong Gong
Chemical Society Reviews 2012 vol. 41(Issue 11) pp:4218-4244
Publication Date(Web):10 Apr 2012
DOI:10.1039/C2CS15359A
Ethylene glycol (EG) is an important organic compound and chemical intermediate used in a large number of industrial processes (e.g. energy, plastics, automobiles, and chemicals). Indeed, owing to its unique properties and versatile commercial applications, a variety of chemical systems (e.g., catalytic and non-catalytic) have been explored for the synthesis of EG, particularly via reaction processes derived from fossil fuels (e.g., petroleum, natural gas, and coal) and biomass-based resources. This critical review describes a broad spectrum of properties of EG and significant advances in the prevalent synthesis and applications of EG, with emphases on the catalytic reactivity and reaction mechanisms of the main synthetic methodologies and applied strategies. We also provide an overview regarding the challenges and opportunities for future research associated with EG.
Co-reporter:Gaowei Wu, Chengxi Zhang, Shuirong Li, Zhiqi Huang, Suli Yan, Shengping Wang, Xinbin Ma and Jinlong Gong
Energy & Environmental Science 2012 vol. 5(Issue 10) pp:8942-8949
Publication Date(Web):07 Jun 2012
DOI:10.1039/C2EE21995F
This paper describes the sorption of carbon dioxide for enhanced steam reforming of ethanol to produce hydrogen via Ni–CaO–Al2O3 multifunctional catalysts derived from hydrotalcite-like compounds (HTlcs). The catalysts were characterized by N2 adsorption–desorption, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR) and thermogravimetric analysis (TGA) and tested in sorption enhanced steam reforming of ethanol (SESRE), in which products were monitored by an online mass spectrometer (MS). The Ni–CaO–Al2O3 catalysts possess uniform distribution of Ni, Ca and Al, contributing significantly to the excellent CO2 adsorbent capacity and reforming activity in SESRE. We have also examined the effect of Ca/Al ratios on Ni dispersion, CaO particle size, and catalytic reactivity; a Ca/Al of 3.0 was optimized. The Ni–CaO–Al2O3 catalysts outperform the conventional mixture of CaO adsorbents and Ni/Al2O3 catalysts for SESRE.
Co-reporter:Jie He ; Maria Teresa Perez ; Peng Zhang ; Yijing Liu ; Taarika Babu ; Jinlong Gong ;Zhihong Nie
Journal of the American Chemical Society 2012 Volume 134(Issue 8) pp:3639-3642
Publication Date(Web):February 9, 2012
DOI:10.1021/ja210844h
Asymmetric multicomponent nanoparticles (AMNPs) offer new opportunities for new-generation materials with improved or new synergetic properties not found in their individual components. There is, however, an urgent need for a synthetic strategy capable of preparing hybrid AMNPs with fine-tuned structural and compositional complexities. Herein, we report a new paradigm for the controllable synthesis of polymer/metal AMNPs with well-controlled size, shape, composition, and morphology by utilizing interfacial polymerization. The hybrid AMNPs display a new level of structural–architectural sophistication, such as controlled domain size and the number of each component of AMNPs. The approach is simple, versatile, cost-effective, and scalable for synthesizing large quantities of AMNPs. Our method may pave a new route to the design and synthesis of advanced breeds of building blocks for functional materials and devices.
Co-reporter:Jie He, Peng Zhang, Jinlong Gong and Zhihong Nie
Chemical Communications 2012 vol. 48(Issue 59) pp:7344-7346
Publication Date(Web):08 May 2012
DOI:10.1039/C2CC32070C
This communication describes a one-step strategy for the facile synthesis of polymer–Au patchy particles (PPs) and Au nanocups using the interfacial reactions.
Co-reporter:Shuirong Li, Chengxi Zhang, Peng Zhang, Gaowei Wu, Xinbin Ma and Jinlong Gong
Physical Chemistry Chemical Physics 2012 vol. 14(Issue 12) pp:4066-4069
Publication Date(Web):16 Jan 2012
DOI:10.1039/C2CP24089K
This paper describes a strategy for producing hydrogenviasteam reforming of ethylene glycol over supported nickel catalysts. Nickel plays a crucial role in conversion of ethylene glycol and production of hydrogen, while oxide supports affect product distribution of carbonaceous species. A plausible reaction pathway is proposed based on our results and the literature.
Co-reporter:Chengxi Zhang, Peng Zhang, Shuirong Li, Gaowei Wu, Xinbin Ma and Jinlong Gong
Physical Chemistry Chemical Physics 2012 vol. 14(Issue 10) pp:3295-3298
Publication Date(Web):21 Dec 2011
DOI:10.1039/C2CP24059A
This paper describes the utilization of skeletal Ni-based catalysts for steam reforming of ethanol to produce CO-free hydrogen, which could be superior in the application of fuel cells. Assistant metals play different roles in the reaction; Pt and Cu suppress the methanation and enhance H2 production, while Co promotes the methanation.
Co-reporter:Qingsen Meng, Yongli Shen, Jing Xu, Xinbin Ma, Jinlong Gong
Surface Science 2012 Volume 606(21–22) pp:1608-1617
Publication Date(Web):November 2012
DOI:10.1016/j.susc.2012.06.014
This paper describes the reaction pathways for hydrogenation of acetaldehyde on atomic hydrogen pre-adsorbed Au(111) employing density functional theory (DFT) calculations. All the surface species involved in the reaction scheme have low diffusion barriers, suggesting that the rearrangement and movement of these species on the surface are facile under reaction condition. The hydroxyethyl is proposed to be the intermediate for the hydrogenation of acetaldehyde, and the activation energy for its formation is 0.37 eV. Additionally, the coupling reaction of hydroxyethyl and acetaldehyde – resulting in the formation of the ethylidene ethylene glycol (CH3C⁎HOCH(CH3)OH) species – also readily occurs at the reaction condition. Two-dimensional (2-D) polyacetaldehyde ((CH3CHO)2) can be easily hydrogenated to ethylidene ethylene glycol or ethoxy hemiacetal (CH3CH2OCH(CH3)O⁎); the latter can be converted to ethanol and acetaldehyde via further hydrogenation. As the hydrogenation products of ethylidene ethylene glycol and ethoxy hemiacetal, ethoxyethanol (CH3CH2OCH(CH3)OH) can be deeply hydrogenated to hydroxyethyl and ethanol. Our calculations also suggest that the formation of an ethoxyl intermediate is not likely, which agrees with the experimental observation that no deuterated acetaldehydes have been detected in isotopic measurements.Highlights► DFT calculations are used to model hydrogenation reaction of acetaldehyde on atomic hydrogen pre-covered Au(111). ► The mechanism contains hydrogenation, coupling, and disproportionation reactions. ► Rearrangement and diffusion of surface species are facile at reaction condition. ► Activation barriers for elementary steps match with the experimental results.
Co-reporter:Wei Wang, Shengping Wang, Xinbin Ma and Jinlong Gong
Chemical Society Reviews 2011 vol. 40(Issue 7) pp:3703-3727
Publication Date(Web):20 Apr 2011
DOI:10.1039/C1CS15008A
Owing to the increasing emissions of carbon dioxide (CO2), human life and the ecological environment have been affected by global warming and climate changes. To mitigate the concentration of CO2 in the atmosphere various strategies have been implemented such as separation, storage, and utilization of CO2. Although it has been explored for many years, hydrogenation reaction, an important representative among chemical conversions of CO2, offers challenging opportunities for sustainable development in energy and the environment. Indeed, the hydrogenation of CO2 not only reduces the increasing CO2 buildup but also produces fuels and chemicals. In this critical review we discuss recent developments in this area, with emphases on catalytic reactivity, reactor innovation, and reaction mechanism. We also provide an overview regarding the challenges and opportunities for future research in the field (319 references).
Co-reporter:Shengping Wang, Suli Yan, Xinbin Ma and Jinlong Gong
Energy & Environmental Science 2011 vol. 4(Issue 10) pp:3805-3819
Publication Date(Web):21 Apr 2011
DOI:10.1039/C1EE01116B
Carbon dioxide (CO2) is a major greenhouse gas and makes a significant contribution to global warming and climate change. Thus CO2 capture and storage (CCS) have attracted worldwide interest from both fundamental and practical research communities. Alkali-metal-based oxides such as alkali-metal oxides, binary oxides, and hydrotalcite-like compounds are promising adsorbents for CO2 capture because of their relatively high adsorption capacity, low cost, and wide availability. They can also be applied to the adsorption-enhanced reactions involving CO2. The microstructures (e.g., surface area, porosity, particle size, and dispersion) of these oxides determine the CO2 adsorption capacity and multicycle stability. This perspective critically assesses and gives an overview of recent developments in the synthesized method, adsorption mechanism, operational conditions, stability, and regenerability of a variety of oxides. Both pros and cons of these oxides are also discussed. Insights are provided into several effective procedures regarding microstructural control of alkali-metal-based oxides, including preparation optimization, modification, stream hydration, etc.
Co-reporter:Shengping Wang, Yun Shi, Xinbin Ma, and Jinlong Gong
ACS Applied Materials & Interfaces 2011 Volume 3(Issue 6) pp:2154
Publication Date(Web):May 24, 2011
DOI:10.1021/am200380a
This paper describes a method to regulate porosity of Ti-containing mesoporous molecular sieves (Ti-MCM-41) by employing swelling agents that are hydrophobic in nature, such as dodecylamine, n-heptane, and sym-trimethylbenzene (TMB). Physicochemical properties of the samples were investigated using XRD, FT-IR, IR spectra of pyridine absorption, UV–vis, TEM, and N2 adsorption–desorption techniques. Addition of favorable swelling agents leads to an increase in pore size accompanied by retaining the mesostructure with a certain decrease of structure ordering. Swelling agents also have significant impact on the integration of Ti into the silica framework, which further affect the formation of Lewis acid sites. N-heptane is the most favorable agent for pore expansion of Ti-MCM-41. The material with n-heptane/CTAB ratio of 1 exhibits the largest pore size of 48.3 Ǻ, and mesopore volume of 1.266 cm3/g and narrow pore-size distribution. We also demonstrated that shape-selective transesterification catalytic activity of Ti-MCM-41 was greatly enhanced because of pore expansion.Keywords: organic carbonate; pore expansion; shape selectivity; swelling agent; Ti-MCM-41
Co-reporter:Shuang Chen, Shengping Wang, Xinbin Ma and Jinlong Gong
Chemical Communications 2011 vol. 47(Issue 33) pp:9345-9347
Publication Date(Web):18 Jul 2011
DOI:10.1039/C1CC12391B
This communication describes the design of bifunctional VOx/TS-1 catalysts with enhanced redox and acidic character via doping SO42− and PO43− for selective oxidation of methanol to dimethoxymethane. Redox sites enable the production of formaldehyde, while acidic sites favor the condensation of formaldehyde to DMM.
Co-reporter:Jie Pan, Dong Wan and Jinlong Gong
Chemical Communications 2011 vol. 47(Issue 12) pp:3442-3444
Publication Date(Web):07 Feb 2011
DOI:10.1039/C0CC05520D
This paper describes the synthesis and application of PEGylated liposome-coated quantum dots (QDs)/mesoporous silica core–shell nanoparticles (NPs) for molecular imaging. This system increases biocompatibility and stability of QDs, thus improving the imaging effects in labeling of cancer cells.
Co-reporter:Maoshuai Li, Shuirong Li, Chengxi Zhang, Shengping Wang, Xinbin Ma, Jinlong Gong
International Journal of Hydrogen Energy 2011 Volume 36(Issue 1) pp:326-332
Publication Date(Web):January 2011
DOI:10.1016/j.ijhydene.2010.09.084
This paper describes a study regarding the effect of Ni addition to NixMg1−xO solid solutions on the catalytic performances of ethanol steam reforming for hydrogen production. Nickel nanoparticles supported on NixMg1−xO demonstrated higher conversion of ethanol and yields of hydrogen than the bare support. We correlated the improved performances of Ni-based catalysts with the reducibility of nickel species. The addition of Ni to the solid solution support produced more easily reducible surface nickel species. Higher content of bulk nickel species in the support could inhibit the surface nickel species from diffusing into the bulk, leading to more surface nickel species that is easily reducible to its active form.
Co-reporter:Jing Lv, Xinbin Ma, Suli Bai, Chengdu Huang, Zhenhua Li, Jinlong Gong
International Journal of Hydrogen Energy 2011 Volume 36(Issue 14) pp:8365-8372
Publication Date(Web):July 2011
DOI:10.1016/j.ijhydene.2011.04.122
This paper describes a catalytic reaction of hydrogen and carbon monoxide (Fischer–Tropsch synthesis (FTS)) over carbon nanotubes (CNTs) supported cobalt nanoparticles. We have investigated the effect of calcination of the catalysts on FTS performance using X-ray diffraction (XRD), H2 chemisorption, temperature programmed reduction (TPR), temperature programmed oxidation (TPO), and transmission electron microscopy (TEM) techniques. With the increase of outer diameter of CNTs, specific surface area of the catalyst decreases while Co particle size increased accompanying with a decrease in CO conversion. The FTS performance is similar for samples calcined in N2 or air at temperature below 550 °C. Over 550 °C, the results are much different in that the Co/CNTs can keep its activity due to the unchanged CNTs structure in N2 while the Co/CNTs almost lose activity owing to the loss of CNTs structure and sintering of cobalt oxide clusters in air.Highlights► Calcination temperature and ambient condition determine the surface morphology and reactivity of Co/CNTs catalysts. ► The diameter of CNTs and size of Co particles influence CO conversion and selectivity to CH4 and C5+ molecules. ► Calcination in nitrogen atmosphere is favorable for the preparation of CNTs-based catalyst for hydrogenation of CO.
Co-reporter:Jinlong Gong
Catalysis Letters 2011 Volume 141( Issue 4) pp:623-624
Publication Date(Web):2011 April
DOI:10.1007/s10562-010-0539-1
Co-reporter:Wang Wei;Gong Jinlong
Frontiers of Chemical Science and Engineering 2011 Volume 5( Issue 1) pp:2-10
Publication Date(Web):2011 March
DOI:10.1007/s11705-010-0528-3
Although being very challenging, utilization of carbon dioxide (CO2) originating from production processes and flue gases of CO2-intensive sectors has a great environmental and industrial potential due to improving the resource efficiency of industry as well as by contributing to the reduction of CO2 emissions. As a renewable and environmentally friendly source of carbon, catalytic approaches for CO2 fixation in the synthesis of chemicals offer the way to mitigate the increasing CO2 buildup. Among the catalytic reactions, methanation of CO2 is a particularly promising technique for producing energy carrier or chemical. This article focuses on recent developments in catalytic materials, novel reactors, and reaction mechanism for methanation of CO2.
Co-reporter:Yu Chen, Rentao Mu, Mingde Yang, Lina Fang, Yulong Wu, Kejing Wu, Ya Liu, Jinlong Gong
Chemical Engineering Science (6 April 2017) Volume 161() pp:299-307
Publication Date(Web):6 April 2017
DOI:10.1016/j.ces.2016.12.010
•The production of bio-oil via catalytic HTL of D. tertiolecta was carried out over metal/CNTs.•The optimal D. tertiolecta conversion was 95.78% with bio-oil yield of 40.25 wt.% over Co/CNTs.•A plausible reaction mechanism of the main chemical component in D. tertiolecta was proposed.•The catalyst type affected the chemical composition and boiling point distribution of bio-oil.This paper describes catalytic consequence of hydrothermal liquefaction (HTL) of Dunaliella tertiolecta (D. tertiolecta) over carbon nanotubes (CNTs) supported metals catalysts to produce bio-oil. When Co/CNTs is used as catalysts, the conversion and bio-oil yield increase to 95.78 and 40.25 wt.%, respectively. Chemical analysis results showed that the introduction of catalyst significantly affected the chemical composition of bio-oil with a higher percentage of hydrocarbons and a lower content of fatty acid. The introduction of metal into CNTs had no change in the basic CNT skeleton and the loaded metal nanoparticles encapsulated within the CNT enhances the disorder and defects in CNTs. Based on our results and the literature, the plausible general reaction and catalytic HTL pathways of D. tertiolecta are proposed.Download high-res image (153KB)Download full-size image
Co-reporter:Rentao Mu, Zhi-jian Zhao, Zdenek Dohnálek and Jinlong Gong
Chemical Society Reviews 2017 - vol. 46(Issue 7) pp:NaN1806-1806
Publication Date(Web):2017/02/09
DOI:10.1039/C6CS00864J
Understanding water/solid interactions is of great importance in a variety of fundamental and technological processes, such as photocatalytic water splitting, heterogeneous catalysis, electrochemistry, and corrosion. This review describes recent advancements in the molecular-level understanding of water adsorption, dissociation and clustering on model surfaces of metal oxides, achieved primarily by combining scanning probe microscopies with ensemble-averaged techniques and density functional theory calculations. Factors controlling how water binds and clusters on the coordinatively unsaturated metal cations of different oxide surfaces are discussed. We start by reviewing the fundamental differences in the relative stability of molecularly and dissociatively-bonded water monomers and clusters on isostructural rutile TiO2(110) and RuO2(110) surfaces and on different surfaces and polymorphs of TiO2. We further discuss how oxide interfaces (both exposed and buried) with metals affect water dissociation. Subsequently, we focus on high coverage water overlayers such as one-dimensional water chain structures that result from different substrate morphologies, and water monolayer structures. We conclude with novel studies of interfacial water in liquids.
Co-reporter:Jinlong Gong and Xinhe Bao
Chemical Society Reviews 2017 - vol. 46(Issue 7) pp:NaN1771-1771
Publication Date(Web):2017/03/27
DOI:10.1039/C7CS90022H
Surface and interfacial catalysis plays a vital role in chemical industries, electrochemistry and photochemical reactions. The challenges of modern chemistry are to optimize the chemical reaction processes and understand the detailed mechanism of chemical reactions. Since the early 1960s, the foundation of surface science systems has allowed the study of surface and interfacial phenomena on atomic/molecular level, and thus brought a number of significant developments to fundamental and technological processes, such as catalysis, material science and biochemistry, just to name a few. This themed issue describes the recent advances and developments in the fundamental understanding of surface and interfacial catalysis, encompassing areas of knowledge from metal to metal oxide, carbide, graphene, hexagonal boron nitride, and transition metal dichalcogenides under ultrahigh vacuum conditions, as well as under realistic reaction conditions.
Co-reporter:Zhibin Luo, Chengcheng Li, Shanshan Liu, Tuo Wang and Jinlong Gong
Chemical Science (2010-Present) 2017 - vol. 8(Issue 1) pp:NaN100-100
Publication Date(Web):2016/10/03
DOI:10.1039/C6SC03707K
Hematite (α-Fe2O3) is a promising candidate for solar-to-hydrogen energy conversion. However, the low carrier mobility and extremely high charge recombination rate limit the practical application of hematite in solar water splitting. This paper describes the fabrication of a Fe2O3 photoanode with gradient incorporation of phosphorus (P) employing a facile dipping and annealing method to improve the charge separation for enhanced photoelectrochemical water oxidation. This gradient P incorporation increases the width of band bending over a large region in Fe2O3, which is crucial for promoting the charge separation efficiency in the bulk. Although both gradient and homogeneous P-incorporated Fe2O3 samples exhibit similar electrical conductivity, the Fe2O3 electrode with a gradient P concentration presents an additional charge separation effect. A photocurrent of ∼1.48 mA cm−2 is obtained at 1.23 V vs. reversible hydrogen electrode (vs. RHE) under air mass 1.5G illumination. Additionally, the H2O oxidation kinetics of Fe2O3 with gradient P incorporation was further improved upon loading cobalt phosphate as cocatalyst, reaching a photocurrent of ∼2.0 mA cm−2 at 1.23 V vs. RHE.
Co-reporter:Shengbo Zhang, Hua Wang, Mei Li, Jinyu Han, Xiao Liu and Jinlong Gong
Chemical Science (2010-Present) 2017 - vol. 8(Issue 6) pp:NaN4496-4496
Publication Date(Web):2017/04/19
DOI:10.1039/C7SC00713B
Heterogeneous metal complex catalysts for direct C–H activation with high activity and durability have always been desired for transforming raw materials into feedstock chemicals. This study described the design and synthesis of one-dimensional organosilica nanotubes containing 2,2′-bipyridine (bpy) ligands in the framework (BPy-NT) and their post-synthetic metalation to provide highly active and robust molecular heterogeneous catalysts. By adjusting the ratios of organosilane precursors, very short BPy-NT with ∼50 nm length could be controllably obtained. The post-synthetic metalation of bipyridine-functionalized nanotubes with [IrCp*Cl(μ-Cl)]2 (Cp* = η5-pentamethylcyclopentadienyl) and [Ir(cod)(OMe)]2 (cod = 1,5-cyclooctadiene) afforded solid catalysts, IrCp*-BPy-NT and Ir(cod)-BPy-NT, which were utilized for C–H oxidation of heterocycles and cycloalkanes as well as C–H borylation of arenes. The cut-short nanotube catalysts displayed enhanced activities and durability as compared to the analogous homogeneous catalysts and other conventional heterogeneous catalysts, benefiting from the isolated active sites as well as the fast transport of substrates and products. After the reactions, a detailed characterization of Ir-immobilized BPy-NT via TEM, SEM, nitrogen adsorption, UV/vis, XPS, and 13C CP MAS NMR indicated the molecular nature of the active species as well as stable structures of nanotube scaffolds. This study demonstrates the potential of BPy-NT with a short length as an integration platform for the construction of efficient heterogeneous catalytic systems for organic transformations.
Co-reporter:Jijie Zhang, Tuo Wang, Xiaoxia Chang, Ang Li and Jinlong Gong
Chemical Science (2010-Present) 2016 - vol. 7(Issue 10) pp:NaN6386-6386
Publication Date(Web):2016/06/24
DOI:10.1039/C6SC01803C
Most Bi-based photoelectrodes have suitable band gaps and can effectively promote the water oxidation reaction. However, simple preparation methods for Bi-based binary metal oxides as photoanodes are scarce. This paper describes a simple hydrothermal anion exchange method to synthesize Bi-based binary metal oxides with controlled morphologies. This synthesis process uses BiOI as the template and Bi source, which is eventually converted to Bi-based porous nanoflake photoanodes upon reaction with MOx (M = W, V, and Mo)-containing precursors. The photoanodes show well-shaped porous nanoflake morphologies and exhibit impressive photoelectrochemical properties compared to Bi-based photoanodes synthesized by conventional methods. These three samples possess long-term stability under solar irradiation and show considerable photocurrent for sulfite oxidation.
Co-reporter:Peng Zhang, Tuo Wang and Jinlong Gong
Chemical Communications 2016 - vol. 52(Issue 57) pp:NaN8809-8809
Publication Date(Web):2016/06/03
DOI:10.1039/C6CC03411J
This paper describes the fabrication of TiO2 overlayers by atomic layer deposition to passivate the surface states on Ta3N5 thin film anodes for photoelectrochemical water oxidation. The removal of surface states reduces the overpotential and decreases the density of surface recombination centers, resulting in enhanced activity through effective utilization of photogenerated charge carriers.
Co-reporter:Peng Zhang, Jie He, Xinbin Ma, Jinlong Gong and Zhihong Nie
Chemical Communications 2013 - vol. 49(Issue 10) pp:NaN989-989
Publication Date(Web):2012/12/12
DOI:10.1039/C2CC37713F
This communication describes a facile method for the synthesis of conical-shaped Au nanoparticles with a hollow cavity by combining interfacial reaction and ultrasonic cavitation. The Au nanocones showed an enhancement factor of 7.7 × 108 in surface enhanced Raman scattering (SERS) detection.
Co-reporter:Jianwei Lu, Peng Zhang, Ang Li, Fengli Su, Tuo Wang, Yuan Liu and Jinlong Gong
Chemical Communications 2013 - vol. 49(Issue 52) pp:NaN5819-5819
Publication Date(Web):2013/04/08
DOI:10.1039/C3CC42029A
This communication describes a method for facile synthesis of mesoporous anatase TiO2 nanocup crystals. The novel cuplike morphology of TiO2 decorated with gold (Au–TiO2) yields remarkably high photocatalytic activity for degradation of methylene blue under visible light irradiation.
Co-reporter:Shuirong Li, Chengxi Zhang, Zhiqi Huang, Gaowei Wu and Jinlong Gong
Chemical Communications 2013 - vol. 49(Issue 39) pp:NaN4228-4228
Publication Date(Web):2012/10/24
DOI:10.1039/C2CC37109J
This communication describes the synthesis of a nanocomposite Ni@ZrO2 catalyst with enhanced metal–support interaction by introducing metal nanoparticles into the framework of the oxide support. The catalyst shows high catalytic activity and stability for hydrogen production via steam reforming of ethanol.
Co-reporter:Chengxi Zhang, Wancheng Zhu, Shuirong Li, Gaowei Wu, Xinbin Ma, Xun Wang and Jinlong Gong
Chemical Communications 2013 - vol. 49(Issue 82) pp:NaN9385-9385
Publication Date(Web):2013/07/22
DOI:10.1039/C3CC43895C
This communication describes the design and synthesis of anti-sintering and -coke nickel phyllosilicate (PS) nanotubes (Ni/PSn) for hydrogen production via reforming reactions. The introduction of nickel particles in PS nanotubes could effectively maintain the Ni size and increase the resistance of metal particles for carbon deposition.
Co-reporter:Jie Pan, Dong Wan and Jinlong Gong
Chemical Communications 2011 - vol. 47(Issue 12) pp:NaN3444-3444
Publication Date(Web):2011/02/07
DOI:10.1039/C0CC05520D
This paper describes the synthesis and application of PEGylated liposome-coated quantum dots (QDs)/mesoporous silica core–shell nanoparticles (NPs) for molecular imaging. This system increases biocompatibility and stability of QDs, thus improving the imaging effects in labeling of cancer cells.
Co-reporter:Zhi-Jian Zhao, Cheng-chau Chiu and Jinlong Gong
Chemical Science (2010-Present) 2015 - vol. 6(Issue 8) pp:NaN4425-4425
Publication Date(Web):2015/06/12
DOI:10.1039/C5SC01227A
Due to the depletion of petroleum and the recent shale gas revolution, the dropping of the price for light alkanes makes alkanes an attractive feedstock for the production of light alkenes and other valuable chemicals. Understanding the mechanism for the activation of C–H bonds in hydrocarbons provides fundamental insights into this process and a guideline for the optimization of catalysts used for the processing of light alkanes. In the last two decades, density functional theory (DFT) has become a powerful tool to explore elementary steps and mechanisms of many heterogeneously catalyzed processes at the atomic scale. This review describes recent progress on computational understanding of heterogeneous catalytic dehydrogenation reactions of light alkanes. We start with a short description on basic concepts and principles of DFT as well as its application in heterogeneous catalysis. The activation of C–H bonds over transition metal and alloy surfaces are then discussed in detail, followed by C–H activation over oxides, zeolites and catalysts with single atoms as active sites. The origins of coking formation are also discussed followed by a perspective on directions of future research.
Co-reporter:Wei Wang, Shengping Wang, Xinbin Ma and Jinlong Gong
Chemical Society Reviews 2011 - vol. 40(Issue 7) pp:NaN3727-3727
Publication Date(Web):2011/04/20
DOI:10.1039/C1CS15008A
Owing to the increasing emissions of carbon dioxide (CO2), human life and the ecological environment have been affected by global warming and climate changes. To mitigate the concentration of CO2 in the atmosphere various strategies have been implemented such as separation, storage, and utilization of CO2. Although it has been explored for many years, hydrogenation reaction, an important representative among chemical conversions of CO2, offers challenging opportunities for sustainable development in energy and the environment. Indeed, the hydrogenation of CO2 not only reduces the increasing CO2 buildup but also produces fuels and chemicals. In this critical review we discuss recent developments in this area, with emphases on catalytic reactivity, reactor innovation, and reaction mechanism. We also provide an overview regarding the challenges and opportunities for future research in the field (319 references).
Co-reporter:Manh Huy Do, Tuo Wang, Dang-guo Cheng, Fengqiu Chen, Xiaoli Zhan and Jinlong Gong
Journal of Materials Chemistry A 2014 - vol. 2(Issue 35) pp:NaN14370-14370
Publication Date(Web):2014/06/12
DOI:10.1039/C4TA01737D
Understanding of the crystal growth mechanism of zeolites is essential for rational design of zeolite materials with desired physical and chemical properties, but still remains elusive. This paper describes experimental findings of zeolite crystal evolution from sodium-rich hydrogels, revealing that the zeolite nucleation occurs at the equilibrated gel phase of the condensed primary aggregates precipitated from the dissolved (alumino)silicate species. The nuclei produced from the nucleation could be diffused into the liquid–solid interface of the equilibrated gel phase and the liquid phase. The zeolite growth therefore occurs through a synergistic mechanism of two growth processes: a solution-mediated process and a solid-state transformation. In the liquid phase and the liquid–gel (equilibrated gel) interface, the oriented aggregation governs the zeolite growth in early stages. The major driving force for the aggregation is the electrostatic force between the positively charged active Na+ and the negative charges of the (TO−) groups on the surface of the nuclei and growing nanocrystals. In the last few steps the crystal growth by the coalescence and the Ostwald rule becomes predominant.
Co-reporter:Chengxi Zhang, Peng Zhang, Shuirong Li, Gaowei Wu, Xinbin Ma and Jinlong Gong
Physical Chemistry Chemical Physics 2012 - vol. 14(Issue 10) pp:NaN3298-3298
Publication Date(Web):2011/12/21
DOI:10.1039/C2CP24059A
This paper describes the utilization of skeletal Ni-based catalysts for steam reforming of ethanol to produce CO-free hydrogen, which could be superior in the application of fuel cells. Assistant metals play different roles in the reaction; Pt and Cu suppress the methanation and enhance H2 production, while Co promotes the methanation.
Co-reporter:Shuirong Li, Chengxi Zhang, Peng Zhang, Gaowei Wu, Xinbin Ma and Jinlong Gong
Physical Chemistry Chemical Physics 2012 - vol. 14(Issue 12) pp:NaN4069-4069
Publication Date(Web):2012/01/16
DOI:10.1039/C2CP24089K
This paper describes a strategy for producing hydrogenviasteam reforming of ethylene glycol over supported nickel catalysts. Nickel plays a crucial role in conversion of ethylene glycol and production of hydrogen, while oxide supports affect product distribution of carbonaceous species. A plausible reaction pathway is proposed based on our results and the literature.
Co-reporter:Fengli Su, Jianwei Lu, Ye Tian, Xinbin Ma and Jinlong Gong
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 29) pp:NaN12032-12032
Publication Date(Web):2013/05/20
DOI:10.1039/C3CP51291F
This paper describes the design, characterization, and utilization of branched TiO2 nanoarrays sensitized with CdS quantum dots as anodes for photoelectrochemical water splitting. The remarkable photocurrent density (∼4 mA cm−2 at a potential of 0 V versus Ag/AgCl) and high solar to hydrogen efficiency of the materials obtained were ascribed to the novel branched nanostructure and efficient electron transfer from CdS to TiO2.
Co-reporter:Jinlong Gong, Zhihong Nie and Xinbin Ma
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 29) pp:NaN11987-11987
Publication Date(Web):2013/06/27
DOI:10.1039/C3CP90089D
A graphical abstract is available for this content
Co-reporter:Shengping Wang, Changjiang Li, Tuo Wang, Peng Zhang, Ang Li and Jinlong Gong
Journal of Materials Chemistry A 2014 - vol. 2(Issue 9) pp:NaN2890-2890
Publication Date(Web):2013/12/04
DOI:10.1039/C3TA14576J
This paper describes a facile and generally feasible method to synthesize nanotube-type graphitic carbon nitride (g-C3N4) by directly heating melamine packed in an appropriate compact degree which plays a crucial role in the formation process of g-C3N4. This approach has several advantages: (i) no templates or extra organics are involved; (ii) high industrial feasibility; (iii) low cost; and (iv) general applicability. The as-synthesized g-C3N4 samples show intense fluorescence with a photoluminescent (PL) peak at 460 nm indicating their potential applications as a blue light fluorescence material. They also exhibit excellent visible-light photocatalytic activity compared to a reference P25 photocatalyst. The method reported may open up new opportunities for further studies as well as practical applications of g-C3N4 nanotubes in fields such as light-emitting devices, gas storage and photocatalysis.
Co-reporter:Hairong Yue, Yujun Zhao, Xinbin Ma and Jinlong Gong
Chemical Society Reviews 2012 - vol. 41(Issue 11) pp:NaN4244-4244
Publication Date(Web):2012/04/10
DOI:10.1039/C2CS15359A
Ethylene glycol (EG) is an important organic compound and chemical intermediate used in a large number of industrial processes (e.g. energy, plastics, automobiles, and chemicals). Indeed, owing to its unique properties and versatile commercial applications, a variety of chemical systems (e.g., catalytic and non-catalytic) have been explored for the synthesis of EG, particularly via reaction processes derived from fossil fuels (e.g., petroleum, natural gas, and coal) and biomass-based resources. This critical review describes a broad spectrum of properties of EG and significant advances in the prevalent synthesis and applications of EG, with emphases on the catalytic reactivity and reaction mechanisms of the main synthetic methodologies and applied strategies. We also provide an overview regarding the challenges and opportunities for future research associated with EG.
Co-reporter:Tuo Wang, Zhibin Luo, Chengcheng Li and Jinlong Gong
Chemical Society Reviews 2014 - vol. 43(Issue 22) pp:NaN7484-7484
Publication Date(Web):2014/02/06
DOI:10.1039/C3CS60370A
Photoelectrochemical (PEC) water splitting is an attractive approach to generate hydrogen as a clean chemical fuel from solar energy. But there remain many fundamental issues to be solved, including inadequate photon absorption, short carrier diffusion length, surface recombination, vulnerability to photo-corrosion, and unfavorable reaction kinetics. Owing to its self-limiting surface reaction mechanism, atomic layer deposition (ALD) is capable of depositing thin films in a highly controllable manner, which makes it an enabling technique to overcome some of the key challenges confronted by PEC water splitting. This tutorial review describes some unique and representative applications of ALD in fabricating high performance PEC electrodes with various nanostructures, including (i) coating conformal thin films on three-dimensional scaffolds to facilitate the separation and migration of photocarriers and enhance light trapping, as well as realizing controllable doping for bandgap engineering and forming homojunctions for carrier separation; (ii) achieving surface modification through deposition of anti-corrosion layers, surface state passivation layers, and surface catalytic layers; and (iii) identifying the main rate limiting steps with model electrodes with highly defined thickness, composition, and interfacial structure.
Co-reporter:Jinlong Gong and Rafael Luque
Chemical Society Reviews 2014 - vol. 43(Issue 22) pp:NaN7468-7468
Publication Date(Web):2014/10/07
DOI:10.1039/C4CS90084G
A graphical abstract is available for this content
Co-reporter:Shuirong Li and Jinlong Gong
Chemical Society Reviews 2014 - vol. 43(Issue 21) pp:NaN7256-7256
Publication Date(Web):2014/09/03
DOI:10.1039/C4CS00223G
Owing to the considerable publicity that has been given to petroleum related economic, environmental, and political problems, renewed attention has been focused on the development of highly efficient and stable catalytic materials for the production of chemical/fuel from renewable resources. Supported nickel nanoclusters are widely used for catalytic reforming reactions, which are key processes for generating synthetic gas and/or hydrogen. New challenges were brought out by the extension of feedstock from hydrocarbons to oxygenates derivable from biomass, which could minimize the environmental impact of carbonaceous fuels and allow a smooth transition from fossil fuels to a sustainable energy economy. This tutorial review describes the recent efforts made toward the development of nickel-based catalysts for the production of hydrogen from oxygenated hydrocarbons via steam reforming reactions. In general, three challenges facing the design of Ni catalysts should be addressed. Nickel nanoclusters are apt to sinter under catalytic reforming conditions of high temperatures and in the presence of steam. Severe carbon deposition could also be observed on the catalyst if the surface carbon species adsorbed on metal surface are not removed in time. Additionally, the production of hydrogen rich gas with a low concentration of CO is a challenge using nickel catalysts, which are not so active in the water gas shift reaction. Accordingly, three strategies were presented to address these challenges. First, the methodologies for the preparation of highly dispersed nickel catalysts with strong metal–support interaction were discussed. A second approach—the promotion in the mobility of the surface oxygen—is favored for the yield of desired products while promoting the removal of surface carbon deposition. Finally, the process intensification via the in situ absorption of CO2 could produce a hydrogen rich gas with low CO concentration. These approaches could also guide the design of other types of heterogeneous base-metal catalysts for high temperature processes including methanation, dry reforming, and hydrocarbon combustion.
Co-reporter:Lei Zhang, Zhaoxiong Xie and Jinlong Gong
Chemical Society Reviews 2016 - vol. 45(Issue 14) pp:NaN3934-3934
Publication Date(Web):2016/04/20
DOI:10.1039/C5CS00958H
Au–Pd nanostructured materials have been recognized as important heterogeneous catalysts in various reactions, due to their superior activities caused by the ensemble and ligand effects. In recent years, shape-controlled synthesis of noble metal nanocrystals (NCs) provided a brand-new insight for improving the performance of catalysts. The electronic properties and catalytic activities of Au–Pd NCs could be optimized by tuning their shape and composition engineering. This review describes recent progress in the design and synthesis of shape-controlled Au–Pd bimetallic NCs and their emerging catalytic applications. The review starts with a general discussion of various applications of Au–Pd catalysts and the significance of preparing shape-controlled Au–Pd NCs, followed by an overview of synthetic strategies for two different structures of Au–Pd bimetallic catalysts: a core–shell structure and an alloy structure. We also put forward the key factors for the preparation of Au–Pd core–shell and alloy structures. Additionally, we discussed the unique optical properties and structural effects of shape-controlled Au–Pd NCs. These recent advancements in the methodology development of Au–Pd bimetallic NCs offer numerous insights for generating Au–Pd NCs with a number of unique geometries in the future. Furthermore, the systematic synthesis of core–shell or alloy structures would provide insights for the preparation of other bimetallic NCs.
Co-reporter:Peng Zhang, Jijie Zhang and Jinlong Gong
Chemical Society Reviews 2014 - vol. 43(Issue 13) pp:NaN4422-4422
Publication Date(Web):2014/03/25
DOI:10.1039/C3CS60438A
Solar energy utilization is one of the most promising solutions for the energy crises. Among all the possible means to make use of solar energy, solar water splitting is remarkable since it can accomplish the conversion of solar energy into chemical energy. The produced hydrogen is clean and sustainable which could be used in various areas. For the past decades, numerous efforts have been put into this research area with many important achievements. Improving the overall efficiency and stability of semiconductor photocatalysts are the research focuses for the solar water splitting. Tantalum-based semiconductors, including tantalum oxide, tantalate and tantalum (oxy)nitride, are among the most important photocatalysts. Tantalum oxide has the band gap energy that is suitable for the overall solar water splitting. The more negative conduction band minimum of tantalum oxide provides photogenerated electrons with higher potential for the hydrogen generation reaction. Tantalates, with tunable compositions, show high activities owning to their layered perovskite structure. (Oxy)nitrides, especially TaON and Ta3N5, have small band gaps to respond to visible-light, whereas they can still realize overall solar water splitting with the proper positions of conduction band minimum and valence band maximum. This review describes recent progress regarding the improvement of photocatalytic activities of tantalum-based semiconductors. Basic concepts and principles of solar water splitting will be discussed in the introduction section, followed by the three main categories regarding to the different types of tantalum-based semiconductors. In each category, synthetic methodologies, influencing factors on the photocatalytic activities, strategies to enhance the efficiencies of photocatalysts and morphology control of tantalum-based materials will be discussed in detail. Future directions to further explore the research area of tantalum-based semiconductors for solar water splitting are also discussed.
Co-reporter:Ang Li, Tuo Wang, Xiaoxia Chang, Weiting Cai, Peng Zhang, Jijie Zhang and Jinlong Gong
Chemical Science (2010-Present) 2016 - vol. 7(Issue 2) pp:NaN895-895
Publication Date(Web):2015/11/26
DOI:10.1039/C5SC04163E
Efficient charge separation is a critical factor for solar energy conversion by heterogeneous photocatalysts. This paper describes the complete spatial separation of oxidation and reduction cocatalysts to enhance the efficacy of charge separation and surface reaction. Specifically, we design Pt@TiO2@MnOx hollow spheres (PTM-HSs) with Pt and MnOx loaded onto the inner and outer surface of TiO2 shells, respectively. Pt favours electron trapping, while MnOx tends to collect holes. Upon generation from TiO2, electrons and holes flow inward and outward of the spherical photocatalyst, accumulating on the corresponding cocatalysts, and then take part in redox reactions. Combined with other advantages, such as the large surface area and appropriate pore size, the PTM-HSs exhibit high efficiency for the photocatalytic oxidation of water and benzyl alcohol. The mechanism of the oxidation process of benzyl alcohol over the photocatalyst is also presented.
Co-reporter:Lei Zhang, Shengnan Yu, Jijie Zhang and Jinlong Gong
Chemical Science (2010-Present) 2016 - vol. 7(Issue 6) pp:NaN3505-3505
Publication Date(Web):2016/03/14
DOI:10.1039/C6SC00083E
Au–Pt bimetallic structures can effectively improve the activity and stability of catalysts in several fuel cell related electrochemical reactions. However, most of the methods for the preparation of Au–Pt nanocrystals (NCs) with core–shell structures are step-wise syntheses, which are adverse for reducing the production costs and the scale-up process. This paper describes a one-pot synthesis of rhombic dodecahedral AuPt@Pt bimetallic nanocrystals with dendritic branches. The dendritic branches on the surfaces were grown through oriented attachment and the whole particle exhibited a single-crystal structure. The thickness of the dendritic Pt shell can be controlled by tuning the introduced Pt precursor. With the Au-enhancement effect arising from the Au–Pt bimetallic core and high atom utilization efficiency provided by the porous structure, the AuPt@Pt bimetallic NCs exhibited greatly enhanced electrocatalytic properties (e.g. oxygen reduction reaction and formic acid oxidation) than those of the commercial Pt/C catalyst.
Co-reporter:Jie He, Peng Zhang, Jinlong Gong and Zhihong Nie
Chemical Communications 2012 - vol. 48(Issue 59) pp:NaN7346-7346
Publication Date(Web):2012/05/08
DOI:10.1039/C2CC32070C
This communication describes a one-step strategy for the facile synthesis of polymer–Au patchy particles (PPs) and Au nanocups using the interfacial reactions.
Co-reporter:Chengxi Zhang, Shuirong Li, Tuo Wang, Gaowei Wu, Xinbin Ma and Jinlong Gong
Chemical Communications 2013 - vol. 49(Issue 90) pp:NaN10649-10649
Publication Date(Web):2013/09/20
DOI:10.1039/C3CC45957H
This communication describes the synthesis of Pt@CeO2 core–shell catalysts for the application of highly efficient CO oxidation, where the 50% CO conversion temperature is lower than 200 °C. Pt@CeO2 is thermally stable as no deactivation occurs during the 70 h reaction, and the morphology is unchanged even after 700 °C thermal treatment.
Co-reporter:Shuang Chen, Shengping Wang, Xinbin Ma and Jinlong Gong
Chemical Communications 2011 - vol. 47(Issue 33) pp:NaN9347-9347
Publication Date(Web):2011/07/18
DOI:10.1039/C1CC12391B
This communication describes the design of bifunctional VOx/TS-1 catalysts with enhanced redox and acidic character via doping SO42− and PO43− for selective oxidation of methanol to dimethoxymethane. Redox sites enable the production of formaldehyde, while acidic sites favor the condensation of formaldehyde to DMM.
Co-reporter:Chengcheng Li, Tuo Wang, Zhibin Luo, Dong Zhang and Jinlong Gong
Chemical Communications 2015 - vol. 51(Issue 34) pp:NaN7293-7293
Publication Date(Web):2015/03/02
DOI:10.1039/C5CC01015B
This communication describes a highly stable ZnO/Ta2O5 photoanode with Ta2O5 deposited by atomic layer deposition. The ultrathin Ta2O5 protective layer prevents corrosion of ZnO and reduces surface carrier recombination, leading to a nearly two-fold increase of photo-conversion efficiency. The transparency of Ta2O5 to sunlight is identified as the main reason for the excellent stability of the photoelectrode for 5 hours.
Co-reporter:Zhibin Luo, Chengcheng Li, Dong Zhang, Tuo Wang and Jinlong Gong
Chemical Communications 2016 - vol. 52(Issue 58) pp:NaN9015-9015
Publication Date(Web):2015/12/07
DOI:10.1039/C5CC09321J
This paper describes the design and synthesis of a heterojunction photoanode composed of highly-oriented Fe2O3/ZnFe2O4 nanocolumnar arrays with a well-defined morphology by reactive ballistic deposition and atomic layer deposition. This specific structure enhances the charge separation at the Fe2O3/ZnFe2O4 interface, leading to an improved photoelectrochemical performance for water oxidation.
