Co-reporter:Xiaojie Yuan, Xuhang Ma, Jun Liao, Fan Ye, Lexi Shao, Feng Peng, and Jun Zhang
ACS Sustainable Chemistry & Engineering August 7, 2017 Volume 5(Issue 8) pp:7325-7325
Publication Date(Web):July 2, 2017
DOI:10.1021/acssuschemeng.7b01547
A chemical-bath deposition method has recently been applied for the industrial deposition of CdS buffer layers in high-efficiency Cu(In, Ga)Se2 (CIGS) solar cells; however, its massive raw material waste and heavy pollution have also hindered its long-range industrialization. In this study, a type of low-pollution and controllable selective-area deposition of CdS thin films on cells was proposed and conducted by a photochemical deposition (PCD) technique using an aqueous solution containing S2O32–, SO32–, and Cd2+. The as-deposited films are low-crystallinity, uniform, and compact with thicknesses of 30–50 nm. Moreover, the depositions of CdS thin films were further investigated by tuning the deposition time, absorption of cadmium ions, sulfur concentration, and light intensity. Additionally, an ion-by-ion mechanism was proposed for the growth of CdS thin films by a PCD technique. Furthermore, the optimal CdS thin layer was applied in CIGS solar cells, which showed a high efficiency of 10.45%. This research would give new insight into the efficient deposition of CdS thin films on solar cells with low pollution.Keywords: CdS thin films; CIGS solar cell; Low pollution; Photochemical deposition (PCD);
Co-reporter:Xixian Yang;Yonghai Cao;Hao Yu;Hongyu Huang;Hongjuan Wang
Catalysis Science & Technology (2011-Present) 2017 vol. 7(Issue 19) pp:4431-4436
Publication Date(Web):2017/10/02
DOI:10.1039/C7CY00958E
The selective oxidation of hydrocarbons is of great importance in the chemical industry. Nanocarbons have attracted intensive attention as metal-free catalysts in this field. Efforts have been made to reveal the crucial role of nanocarbons in the activation of C–H bonds and radical propagation in hydrocarbon oxidation, but it is still far from being understood. In this work, in situ Electron Paramagnetic Resonance (EPR) was conducted in the selective oxidation of cyclohexane (CyH) catalyzed by nitrogen-doped carbon nanotubes (N-CNTs) and multiwalled carbon nanotubes (MWCNTs) in the liquid phase. The interaction between the radicals and nanocarbons was disclosed. The unique role of N-CNTs as a catalyst in the selective oxidation of CyH for the production and propagation of C6H11˙ and O2˙ radicals was evidently confirmed. This work will provide new mechanistic insights into the oxidation of hydrocarbons in the liquid phase.
Co-reporter:Yuan Lin, Siyuan Yang, Yunpeng Liu, Shengsen Zhang, ... Feng Peng
International Journal of Hydrogen Energy 2017 Volume 42, Issue 31(Volume 42, Issue 31) pp:
Publication Date(Web):3 August 2017
DOI:10.1016/j.ijhydene.2017.06.094
•CuO1−x/TiO2 photocatalyst is prepared by a simple in-situ photo-deposition method.•H2-production rate of 1% CuO1−x/TiO2 reaches to 120 times that of TiO2.•The high H2-production activity is ascribed to the highly dispersed CuO1−x clusters.•Low cost Cu can substitute for Pt cocatalyst for photocatalytic hydrogen production.•Small amount Cu greatly improves the activity of Pt/TiO2 for overall water-splitting to H2.CuO1−x cluster-modified TiO2 (CuO1−x/TiO2) photocatalysts were prepared by an in-situ photoreduction deposition of Cu on TiO2 powder support using copper acetate as a Cu source. The prepared samples without any Pt co-catalyst present an especially high photocatalytic H2-evolution activity under solar light irradiation with 5% glycerol as sacrificial agent. The optimal CuO1−x/TiO2 catalyst with only 1 wt% CuO1−x exhibits a high activity of 1725 μmol h−1 g−1 for H2 evolution, which reaches 120 times that of TiO2. The high photocatalytic activity of H2 production is attributed to the highly dispersed CuO1−x nano clusters on the surface of the TiO2. In addition, Pt/CuO1−x/TiO2 was also prepared by loading Pt on CuO1−x/TiO2 sample, and its photocatalytic hydrogen evolution activity is enhanced 1.8 times compared with that of Pt/TiO2 for overall water splitting reaction under solar light, demonstrating that a small amount CuO1−x wondrously improves the photocatalytic activity of Pt/TiO2 for overall water splitting reaction. This paper reports an economic and simple approach to prepare a photocatalyst with high hydrogen-production activity.The CuO1−x/TiO2 catalyst with only 1 wt% CuO1−x as a co-catalyst exhibited a high H2 evolution rate of 1725 μmol h−1 g−1, which reaches 120 times that of pure TiO2 under simulated solar light irradiation.Download high-res image (139KB)Download full-size image
Co-reporter:Shengsen Zhang, Xiujie Wang, Jiayuan Hu, Zhikun Xie, Hougen Lei, Feng Peng
Electrochimica Acta 2017 Volume 252(Volume 252) pp:
Publication Date(Web):20 October 2017
DOI:10.1016/j.electacta.2017.08.164
•Rutile TiO2 nanorods grown rutile(BTNRs) and anatase (ATNRs) branches are designed.•Photoelectrochemical (PEC) performances of BTNRs and ATNRs are comparably evaluated.•ATNRs show a higher PEC activity than BTNRs due to a lower intrinsic resistance.•Heterophase branched structure of anatase and rutile is proven to be more effective.Two kinds of branched TiO2 nanorods arrays (TNRs), i.e. rutile nanorod covered with rutile branches (BTNRs) and rutile nanorod covered with anatase branches (ATNRs), were synthesized on FTO films as photoanodes. Photoelectrochemical (PEC) performances of the both photoanodes were comparably evaluated. The PEC hydrogen production rate of ATNRs photoanode is 4.2 and 2.7 times those of the TNRs and BTNRs photoanodes, respectively. The ATNRs showed a highly PEC response because of a lower intrinsic resistance and a heterophase structure between rutile nanorod and anatase branches. The study explicitly ascertains a kind of more effective structure for photoelectrical materials and gives new insight into intrinsic resistance based on PEC analyses.Download high-res image (174KB)Download full-size imageRutile TiO2 nanorods grown anatase branches show a higher photoelectrochemical activity than grown rutile ones because of a lower intrinsic resistance and a heterophase structure between anatase branches and rutile trunks.
Co-reporter:Ruijing Lv, Hongjuan Wang, Hao Yu, Feng Peng
Electrochimica Acta 2017 Volume 228(Volume 228) pp:
Publication Date(Web):20 February 2017
DOI:10.1016/j.electacta.2017.01.024
•The size and the density of holes on graphene are controlled by a simple method.•The formation mechanism of holey graphene is proposed.•Holey graphene shows good activity and stability for oxygen reduction reaction (ORR).•The defects, conductivity and ORR performance are quantitatively correlated.Defects or pinholes in graphene are important for tuning its properties to be applicable in various fields, such as supercapacitor and oxygen reduction reaction (ORR). Here, we report a simple carbothermal method to controllably form defects or pinholes in graphene by reacting graphene with CoOx in argon atmosphere. The morphology of defects or pores and the reaction mechanism were investigated and discussed detailedly. The defects, the conductivity and the ORR performance in alkaline electrolyte of the holey graphene were quantitatively analyzed and correlated. The results show that the optimized annealing temperature is 700 °C based on the ORR activity. The content of defects or edge carbon atoms of holey graphene, that is the defect density (nD), determining factor for the ORR activity, can be controlled by controlling the pore size and the density in the basal plane of graphene that was realized by adjusting the cobalt content in the precursor. 10Co/G-700-HCl, possessing the highest edge or defective carbon content, reveals the optimal ORR performance with mixed 4e− and 2e− ORR process, excellent stability and good methanol tolerance.Download high-res image (206KB)Download full-size image
Co-reporter:Binhao Qin, Hongjuan Wang, Feng Peng, Hao Yu, Yonghai Cao
Journal of CO2 Utilization 2017 Volume 21(Volume 21) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.jcou.2017.07.012
•The surface roughness of copper foil can be controlled by electropolishing time.•Three-dimensional tin electrode on polished foil is prepared by electrochemical deposition.•Energy efficiency for electroreduction of CO2 to HCOOH is dependent on roughness of foil.•The important dependence of electrode stability on foil roughness is revealed.•Tin electrode on the smoothest foil Exhibits 90% of faradaic efficiency to HCOOH.The tin electrode with three-dimensional (3D) porous structure was prepared using copper foil as the substrate by electrochemical deposition method for the electrochemical reduction of CO2 into HCOOH. The results indicate that the faradaic efficiency (FE) and the energy conversion efficiency (EE) of CO2 to HCOOH are dependent on the surface roughness of copper foil that can be controlled by the electropolishing time. The prepared 3D tin electrode on the smoothest Cu foil exhibits the highest FE (90%) and EE (50%) at −1.2 V (vs. RHE), which were 1.6 times those on the original copper foil. Meanwhile, the Sn loss ratio of this electrode in the electrochemical process is the lowest, showing good stability.Download high-res image (264KB)Download full-size image
Co-reporter:Xiaojie Yuan, Junhui Yi, Hongjuan Wang, Hao Yu, Shanqing Zhang, Feng Peng
Materials Chemistry and Physics 2017 Volume 196(Volume 196) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.matchemphys.2017.05.003
•Highly dispersed Bi nanoparticles (NPs) are prepared by a simple electrodeposition.•Bi NPs are uniformly loaded on the surface of the TiO2 nanotube arrays (TNAs).•The optimal electrodeposition conditions of Bi-TNAs are obtained successfully.•Bi2O3-TNAs and BiOI-TNAs are successfully prepared using the Bi-TNAs.•Bi-based catalysts exhibit the enhanced photocatalytic activity under visible-light.Well dispersed Bi nanostructures were synthesized on TiO2 nanotube arrays (TNAs) via a facile electrochemical deposition route at room temperature, employing Bi(NO3)3·5H2O as the reactant with the assistance of complexing agent and surfactant. The structures of the as-prepared product were characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction and energy dispersive spectrometer. The influence of preparation conditions on Bi electrodeposition were investigated systematically. The results showed that the concentration of surfactant, the deposition voltage and pH value could markedly affect the morphology of Bi-TNAs. The prepared Bi-TNAs have been used to fabricate BiOI and Bi2O3 semiconductors supported on TNAs, which exhibited high visible-light photocatalytic efficiency for acid orange II degradation. This study predicates a promising path to synthesizing Bi-based photocatalysts on TNAs.Download high-res image (236KB)Download full-size image
Co-reporter:Yajun Fang, Hongjuan Wang, Hao Yu, Feng Peng
Electrochimica Acta 2016 Volume 213() pp:273-282
Publication Date(Web):20 September 2016
DOI:10.1016/j.electacta.2016.07.121
•N, S co-doped bio-carbon flocs (NSC) are prepared from chicken feather.•NSC shows excellent oxygen reduction reaction(ORR) nature in acid and alkali media.•The growth mechanism of NSC has been successfully discovered.•A new preparation method of bio-carbon materials from waste biomass is presented.Nitrogen and sulfur co-doped bio-carbon flocs (NSC) with large BET surface areas and porous structures are obtained via pyrolysis of zinc-based metal-organic coordination polymer (MOCP-Zn) that is synthesized through a hydrothermal reaction between zinc salt and polypeptides derived from chicken feather. The as-prepared carbon flocs exhibit a superior performance towards oxygen reduction reaction (ORR) both in alkaline and acid media. Especially, the as-prepared NSC-3.5 can be comparative to Pt/C, exhibiting a promising application in the acidic environment of the proton exchange membrane fuel cell. It is proven that the enhanced ORR activities can be attributed to the high content of pyridinic- and graphitic-type nitrogen and large surface areas with abundant porous structures. Moreover, the growth mechanism of nitrogen and sulfur co-doped bio-carbon materials from chicken feather via coordination reaction and biomineralization process is investigated. This study develops a new method to prepare nonmetal-doped bio-carbon materials from waste biomass with enhanced electrocatalytic performances for ORR.Nitrogen and sulfur co-doped bio-carbon flocs (NSC) derived from chicken feather were successfully obtained, which exhibits superior oxygen reduction reaction (ORR) activity and long-term stability in both acid and alkaline media.
Co-reporter:Yumei Chi, Mingli Zhu, Yuhang Li, Hao Yu, Hongjuan Wang and Feng Peng
Catalysis Science & Technology 2016 vol. 6(Issue 7) pp:2396-2402
Publication Date(Web):19 Nov 2015
DOI:10.1039/C5CY01631B
It is of particular interest to reveal the influence of surface oxygenated groups and surface defects of carbon catalysts on liquid phase oxidation reactions. Herein, surface oxygenated groups and defects were introduced on the surface of carbon nanotubes (CNTs) using a gas-phase oxidation method with O2 and a liquid-phase oxidation method with concentrated HNO3. The results strongly confirm that the surface oxygenated groups on CNTs have a negative effect on catalytic activity for cumene oxidation. To the best of our knowledge, for the first time, we have distinguished experimentally that the factor responsible for the decrease in catalytic activity of the oxidized CNTs for the liquid phase aerobic oxidation reaction is the surface oxygenated groups instead of the surface defects. Meanwhile, the mechanism that drives the decrease in catalytic activity of the oxidized CNTs has also been revealed. It has been proven that the oxidized CNTs serve as free radical quenchers, capturing the free radical intermediates of the reaction and inhibiting the free radical chain transfer, thereby reducing the catalytic activity of the free radical reaction in the liquid phase. This study gains a new insight into the effect of surface structures on carbon-catalyzed liquid phase oxidation, and further pushes forward the research on carbon catalysis.
Co-reporter:Xiujie Wang, Shengsen Zhang, Yaobin Xie, Hongjuan Wang, Hao Yu, Yixing Shen, Zihao Li, Shanqing Zhang, Feng Peng
International Journal of Hydrogen Energy 2016 Volume 41(Issue 44) pp:20192-20197
Publication Date(Web):26 November 2016
DOI:10.1016/j.ijhydene.2016.09.029
•A novel branched hydrogenated TiO2 nanorod array (B/H-TNRs) is designed and prepared.•The hydrogen yield on B/H-TNRs is 4.7 times that on H-TNRs under solar light.•This design promotes the transfer of charges and enhances photocurrent.Two kinds of branched hydrogenated TiO2 nanorod arrays, i.e., hydrogenated TiO2 nanorod supported hydrogenated TiO2 branch arrays (H-BTNRs) and hydrogenated TiO2 nanorod supported unhydrogenated TiO2 branch arrays (B/H-TNRs), have been successfully designed and prepared by a facile approach. Under simulated solar light, the prepared B/H-TNRs have the highest hydrogen evolution rate of 6.65 μmol cm−2 h−1, which is 4.7 and 2.4 times those of hydrogenated TiO2 nanorod arrays (H-TNRs) and H-BTNRs, respectively. This study indicates that the heterostructure design of the unhydrogenated TiO2 branch and hydrogenated TiO2 nanorod promotes the separation of charge carries on the interface and enhances photocatalytic hydrogen evolution.
Co-reporter:Yingsi Wu, Liang Zhan, Kuntao Huang, Hongjuan Wang, Hao Yu, Suqing Wang, Feng Peng, Chunyan Lai
Journal of Alloys and Compounds 2016 Volume 684() pp:47-54
Publication Date(Web):5 November 2016
DOI:10.1016/j.jallcom.2016.05.151
•Dual-metal oxide particles were homogeneously supported on graphene.•CoFe2O4 nanoparticles display superior electrochemical performance as LIB anodes.•Phase pure dual-metal oxide particles can be hollowed by applying Kirkendall effect.•Solid nanosized dual-metal oxides have superior capacity to the hollow spheres.Dual-transition-metal oxide (DTMO) nanostructures are emerging materials for lithium-ion battery (LIB) anodes with improved structural stability, electronic conductivity and electrochemical performance compared to their single-metal counterpart. Herein, composites of graphene with DTMOs (MFeO, M = Co, Mn, Zn) were controllably prepared by harnessing the synthesis atmospheres and the nanoscale diffusion couple. Their composition and morphology were characterized by TEM, EDS mappings, XRD and XPS. The NH3 treatment resulted in the formation of hollow DTMO nanoparticles on nitrogen-doped graphene, while H2 and Ar gave graphene-supported hollow and solid DTMO particles, respectively. Electrochemical tests were applied to compare the performance of these composites as LIB anodes. The superior anode performance DTMO electrodes was demonstrated to the corresponding iron oxide composite. CoFe2O/RGO composites exhibit excellent rate capability and high-rate cycling stability for lithium storage, due to its stable solid structure. However, the hollowing of DTMO particles cannot elevate the capacity and stability, due to the interfacial resistance and structural changes upon cycling.
Co-reporter:Siyuan Yang, Hongjuan Wang, Hao Yu, Shengsen Zhang, Yueping Fang, Shanqing Zhang, Feng Peng
International Journal of Hydrogen Energy 2016 Volume 41(Issue 5) pp:3446-3455
Publication Date(Web):9 February 2016
DOI:10.1016/j.ijhydene.2015.12.190
•The rice-like nitrogen doped titanium dioxide (N-TiO2) is synthesized.•Hierarchical Ag nanoparticles are auto-decorated on N-TiO2 (h-Ag/N-TiO2).•The photoinduced growth process of self-assembled h-Ag/N-TiO2 is revealed.•Photocatalyst h-Ag/N-TiO2 exhibits a high hydrogen production rate under solar light.•Photocatalytic mechanism of photo-splitting ethanol into hydrogen is discussed.The hierarchical Ag NPs with a bimodal size distribution were auto-decorated on the surface of rice-like N-TiO2 (named h-Ag/N-TiO2) by semiconductor-metal double excitation process under solar light irradiation. The photoinduced growth process of self-assembled h-Ag/N-TiO2 and its photocatalytic mechanism of photo-splitting ethanol into hydrogen have been discussed in detail. The synthesized h-Ag/N-TiO2 as a plasmonic photocatalyst for photo-splitting ethanol exhibited a higher hydrogen production rate (4.7 mmol h−1 g−1) than Ag NPs universally loaded N-TiO2 (3.4 mmol h−1 g−1) and pure N-TiO2 (2.1 mmol h−1 g−1). This work presents a reversed photo-induced synthesis strategy to design a stable Ag-TiO2 plasmonic photocatalyst with high photocatalytic efficiency under solar light. A better understanding of this solar light induced self-assembled process for Ag-TiO2 is crucial in developing metal-semiconductor system for solar energy materials.Hierarchical Ag NPs with a bimodal size distribution are auto-decorated on the surface of rice-like N-TiO2 (named h-Ag/N-TiO2) by a reversed photo-induced synthesis method. The synthesized h-Ag/N-TiO2 as a plasmonic photocatalyst for ethanol photo-splitting exhibits an enhancement photocatalytic hydrogen production rate under solar light.
Co-reporter:Xiujie Wang, Shengsen Zhang, Biyu Peng, Hongjuan Wang, Hao Yu, Feng Peng
Materials Letters 2016 Volume 165() pp:37-40
Publication Date(Web):15 February 2016
DOI:10.1016/j.matlet.2015.11.103
•Co nanoparticles are uniformly deposited on the TiO2 nanotube arrays (TNAs).•Co/TNAs exhibits a high activity for photocatalytic splitting of water into hydrogen.•The hydrogen evolution rate of Co/TNAs is near 10 times as high as that of TNAs.•Co as a co-photocatalyst instead of Pt is proven to be feasible and practical.Non-noble metals are attractive alternatives to Pt co-catalysts for hydrogen production. Herein, Co nanoparticles were designed to uniformly deposit on the surface of TiO2 nanotube arrays (Co/TNAs) via photo-deposition and reduction method. The structure and optical property of the Co/TNAs were characterized. Compared with pure TNAs, Co/TNAs showed a highly photocatalytic activity for hydrogen production without the Pt co-catalyst under UV–vis light irradiation. The study presents a promising practical way using non-noble metal as co-catalyst for photocatalytic splitting of water into hydrogen.Co nanoparticles have been uniformly supported on TiO2 nanotube arrays (Co/TNAs), which exhibit a high activity for photocatalytic splitting of water into hydrogen.
Co-reporter:Yingsi Wu, Qianqian Shi, Yuhang Li, Zhuangchai Lai, Hao Yu, Hongjuan Wang and Feng Peng
Journal of Materials Chemistry A 2015 vol. 3(Issue 3) pp:1142-1151
Publication Date(Web):18 Nov 2014
DOI:10.1039/C4TA03850A
A new catalyst, cobalt carbonitride (CoCN) nanoparticles supported on nitrogen-doped graphenes (NG), was synthesized via a high temperature ammonia nitridation method. The catalyst has a core–shell structure with a highly active CoCN core and a protective cobalt oxide shell. Linear sweep voltammetry measurements show that the catalyst presents excellent activity in an oxygen reduction reaction compared to cobalt oxide supported on NG and commercial Pt/C catalysts, benefiting from the strong synergistic effect between CoCN and NG and the electronic modification of cobalt oxide by CoCN from within.
Co-reporter:Guoyu Zhong, Hongjuan Wang, Hao Yu, Feng Peng
Journal of Power Sources 2015 Volume 286() pp:495-503
Publication Date(Web):15 July 2015
DOI:10.1016/j.jpowsour.2015.04.021
•N-doped carbon nanotube with encapsulated Fe3C(Fe3C@NCNT) is prepared by pyrolysis.•Fe3C@NCNT shows good O2 reduction reaction (ORR) nature in acid and alkali media.•Fe3C is encapsulated in the interior and N is distributed on the outside of CNTs.•The inner Fe3C with outside C form synergetic active sites to enhance ORR activity.•A direct four electron ORR path on Fe3C@NCNT is proved in acid and alkali media.Nitrogen doped carbon nanotubes (NCNTs) with encapsulated Fe3C nanoparticles (Fe3C@NCNTs) are synthesized by a simple direct pyrolysis of melamine and ferric chloride. The characterization results reveal that Fe3C is mainly encapsulated in the interior of NCNTs and N species is mainly distributed on the outside surface of NCNTs. Iron and iron carbide catalyze the growth of NCNTs and are wrapped by carbon to form Fe3C@NCNTs. The as-prepared Fe3C@NCNTs catalyst exhibits superior oxygen reduction reaction (ORR) activity, excellent methanol tolerance and long-term stability in both acid and alkaline media. It is proven that the doped N is the main active site for ORR and the inner Fe3C with outside carbon form the synergetic active site to enhance ORR activity. The ORR mechanism of direct four electron transfer pathway is proved in acid and alkaline media.Fe3C nanoparticles coated by several clingy graphitic layers are encapsulated in the interior of N-doped carbon nanotubes (Fe3C@NCNTs), which exhibits superior oxygen reduction reaction activity and long-term stability in both acid and alkaline media. This study has revealed the growth mechanism of Fe3C@NCNTs, and unraveled the catalytic active sites and mechanism for ORR.
Co-reporter:Xiang Li, Hongjuan Wang, Hao Yu, Ziwu Liu, Haihui Wang, Feng Peng
Electrochimica Acta 2015 Volume 185() pp:178-183
Publication Date(Web):10 December 2015
DOI:10.1016/j.electacta.2015.10.128
•Pt-cobalt phosphide catalyst supported on carbon nanotubes (Pt/CoP/CNTs) is designed.•Pt/CoP/CNTs exhibit high activity and stability for methanol oxidation reaction(MOR).•The effect of CoP content on electrocatalytic performances for MOR is studied.•CoP decreases the Pt particle size and increases the electrochemical surface areas.•The interaction between Pt and CoP is evidenced by X-ray photoelectron spectroscopy.In this study, carbon nanotubes (CNTs) supported Pt-cobalt phosphide (CoP) electrocatalyst (Pt/CoP/CNTs) is designed and prepared for methanol oxidation (MOR) for the first time. The modification of CoP decreases the Pt particle size significantly and increases the electrochemical surface areas due to the interaction between Pt and CoP, which is evidenced by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Among all these catalysts, Pt/4%CoP/CNTs catalyst exhibits the best MOR activity of 1600 mA mg−1Pt, which is six times that of Pt/CNTs. Moreover, this catalyst also exhibits the higher onset current density and steady current density than the other Pt-based catalysts. The work provides a promising method to develop the highly active and stable Pt-based catalyst for direct methanol fuel cells.A novel Pt/CoP/CNTs electrocatalyst with has been designed and prepared, which exhibits high activity and stability for methanol oxidation reaction.
Co-reporter:Yonghai Cao, Yuhang Li, Hao Yu, Feng Peng and Hongjuan Wang
Catalysis Science & Technology 2015 vol. 5(Issue 8) pp:3935-3944
Publication Date(Web):17 Mar 2015
DOI:10.1039/C5CY00136F
Carbon nanotubes (CNTs) and nitrogen-doped CNTs (NCNTs) as metal-free catalysts exhibited an excellent activity in the selective oxidation of α-pinene with molecular oxygen as the terminal oxidant. Two distinct pathways, i.e. epoxidation and allylic oxidation, were active in this reaction. Enhancement of epoxidation was observed over CNTs, yielding the highest epoxidation/allylic oxidation products ratio. Excellent activity was achieved over NCNTs, giving 54.5% α-pinene conversion and 272.4 mmol g−1 h−1 mass-normalized activity, which compete with that of the state-of-the-art metal catalysts. Allylic oxidation was enhanced over NCNTs, using which equimolar amounts of epoxide and allylic products were produced. Thus, N-doping boosted the overall conversion and the yields of both epoxidation and allylic oxidation products, which was supported by the results of theoretical simulation.
Co-reporter:Yuhang Li, Guoyu Zhong, Hao Yu, Hongjuan Wang and Feng Peng
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 34) pp:21950-21959
Publication Date(Web):27 Jul 2015
DOI:10.1039/C5CP02167G
It is highly challenging but extremely desirable to develop carbon catalysts with high oxygen reduction reaction (ORR) activity and stability in acidic medium for commercial application. In this paper, based on density functional theory (DFT) calculations with long range interaction correction and solvation effects, the elementary transformations of all the probable intermediates in the ORR and the hydrogen peroxide reduction reaction (HPRR) over graphitic nitrogen-doped carbon nanotubes (NCNTs) in acidic medium were evaluated, and it was found that all the rate determining steps are related to the bonding hydroxyl group because of the strong interaction between the hydroxyl group and carbon. Thus, it is hard for the direct four-electron ORR and the two-electron HPRR to proceed. Together with hydrogen peroxide disproportionation (HPD), a mixed mechanism for the ORR in acidic electrolyte was proposed, where the two-electron and three-electron ORRs and HPD dominate the electrode reaction. The experimental result for the ORR catalyzed by NCNTs in acidic electrolyte also well illustrated the rationality of the theoretical calculations. This study not only gives new insights into the effect of graphitic nitrogen doping on the ORR catalyzed by carbon, but also provides a guide to design carbon catalysts with high ORR activity in acidic electrolyte.
Co-reporter:Yu Zhao, Zhiwei Yao, Yan Shi, Xue Qiao, Guanzhang Wang, Haiyan Wang, Jingzhou Yin and Feng Peng
New Journal of Chemistry 2015 vol. 39(Issue 6) pp:4901-4908
Publication Date(Web):16 Apr 2015
DOI:10.1039/C5NJ00395D
In view of the fact that H2 was necessarily added into gas-state carbon sources in order to remove the surface carbon barrier for the complete carburization of Mo oxides to form Mo carbides, in this paper we proposed a simple synthetic route to overcome this issue. The current approach used a new carbon source, dimethyl ether (DME), as feed gas without H2 addition and employed a pre-heating (PH) method before introducing DME into the reactor. With this novel approach we successfully prepared bulk and CNT supported molybdenum carbides. Note that the removal of carbon deposit by H2 from DME thermal decomposition and PH-induced surface reconstruction can promote the carburization process. The formation mechanism of Mo carbides was proposed using X-ray diffraction (XRD) and rapid heating reaction mass spectrometry (RH-MS) characterizations. The complete synthesis process involved reduction–carburization of Mo precursors by DME and their thermal decomposition product CH4, via the pathway of MoO3/Mo4O11 → MoO2 → MoOxCy/MoC1−x → β-Mo2C. The composition of gas-phase products was predominantly H2, CO and CH4 with a very small amount of CO2 and (or almost no) H2O.
Co-reporter:Shengsen Zhang, Biyu Peng, Siyuan Yang, Hongjuan Wang, Hao Yu, Yueping Fang, Feng Peng
International Journal of Hydrogen Energy 2015 Volume 40(Issue 1) pp:303-310
Publication Date(Web):5 January 2015
DOI:10.1016/j.ijhydene.2014.10.122
•Cu/TiO2 nanotube arrays (Cu/TNAs) are prepared by pulsed electrodeposition method.•The surface plasmon resonance of Cu nanoparticles can be induced by visible light.•Cu/TNAs exhibit high visible-light-driven photocatalytic activity for H2 evolution.•The hydrogen yield on Cu/TNAs is 10.7 times that on TNAs under visible light.Cu nanoparticles (Cu NPs) were successful deposited on the TiO2 nanotube arrays (TNAs) through pulsed electrochemical deposition method. By adjusting the number of deposition cycles, the amount of Cu NPs can be controlled. Compared with pure TNAs, a new strong absorption peak appeared on Cu/TNAs under visible light region due to the surface plasmon resonance (SPR) of Cu NPs. Photoelectrochemical performance and photocatalytic hydrogen evolution characteristic of the Cu/TNAs catalysts were investigated under visible light irradiation. The novel Cu/TNAs heterogenous architectures show a stable and high photocatalytic activity for hydrogen evolution without the Pt co-catalyst.Non-noble metal Cu nanoparticles were loaded on the TiO2 nanotube arrays (Cu/TNAs), which showed an excellent visible-light-driven photocatalytic performance for efficient and stable hydrogen evolution without the Pt co-catalyst due to the surface plasmon resonance (SPR) of Cu nanoparticles.
Co-reporter:Xiujie Wang, Shengsen Zhang, Hongjuan Wang, Hao Yu, Haihui Wang, Shanqing Zhang and Feng Peng
RSC Advances 2015 vol. 5(Issue 93) pp:76315-76320
Publication Date(Web):03 Sep 2015
DOI:10.1039/C5RA15923G
A series of TiO2 nanorod array electrodes with different lengths have been successfully fabricated by a controlled hydrothermal method for photoelectrochemical (PEC) application. In order to enhance the conductivity of the TiO2 nanorods and enable the PEC activity under visible light irradiation, the TiO2 nanorod samples have been further hydrogenated. The influence of the length of the hydrogenated TiO2 nanorod arrays (H-TNRs) on their visible-light-driven photoelectrocatalytic activity was investigated. With increasing the length of the H-TNRs to about 3.0 μm, the activity was close to the maximum. Subsequently, the H-TNRs photoanode was fitted into a thin-layer photoelectrochemical cell for mineralization of organic compounds. The visible light PEC performance was enhanced so much that chemical oxygen demand (COD) detection was achieved under visible light as the light source for the first time. The excellent relationship between the photoelectrochemical COD and conventional COD values within the range of 0–288 mg L−1 suggests that the simple visible light driven PEC method is a promising alternative to the conventional COD method.
Co-reporter:Ziwu Liu, Junfeng Qu, Xin Fu, Quande Wang, Guoyu Zhong, Feng Peng
Materials Letters 2015 Volume 142() pp:115-118
Publication Date(Web):1 March 2015
DOI:10.1016/j.matlet.2014.12.011
•N and P-doped carbon nanotube (NP-CNT) favors the formation of smaller Pt particles.•Pt/NP-CNTs with 0.94 wt% Pt are prepared for the oxygen reduction reaction (ORR).•Pt/NP-CNTs show high activity and stability for ORR in acidic media.•Theoretical calculation reveals the strong interaction between Pt and NP-CNTs.To design low-cost and efficient cathode electrocatalysts and push forward the commercialization of fuel cells, low platinum content catalyst supported on nitrogen and phosphorus-codoped carbon nanotubes (Pt/NP-CNTs) for the oxygen reduction reaction (ORR) were prepared. Electrochemical tests demonstrated that the Pt/NP-CNTs catalyst exhibited much high ORR activity and remarkable stability in acidic media due to the strong interaction between NP-CNT support and Pt catalyst evidenced by the calculation of the density functional theory, showing a good potential application for a future low-cost proton exchange membrane fuel cell device.Pt/NP-CNTs catalyst showed a significantly improved ORR activity and stability in acidic media because of the strong interaction between Pt and NP-CNTs evidenced by DFT calculations.
Co-reporter:Yonghai Cao, Hao Yu, Feng Peng, and Hongjuan Wang
ACS Catalysis 2014 Volume 4(Issue 5) pp:1617
Publication Date(Web):April 9, 2014
DOI:10.1021/cs500187q
Carbon nanotubes (CNTs) and nitrogen-doped CNTs (NCNTs) were systematically investigated as metal-free catalysts in the selective allylic oxidation of cyclohexene using molecular oxygen as oxidant in the liquid phase. High cyclohexene conversion (up to 59.0%) and 620.1 mmol g–1 h–1 mass-normalized activity were obtained for NCNTs, competing with the state-of-the-art metal catalysts. The positive effect of nitrogen dopant on the performance of CNTs was demonstrated, with respect to the aspects of enhancing activity and increasing selectivity of 2-cyclohexen-1-one, allowing for a ketone/alcohol ratio of 3.7 at 59% conversion. The unique catalytic role of NCNTs was attributed to their capability to promote the radical chain propagation via stabilizing peroxyl and cycloxyl radicals, which boosted the further conversion of 2-cyclohexen-1-ol toward 2-cyclohexen-1-one as well.Keywords: aerobic oxidation; allylic oxidation; carbon nanotubes; cyclohexene; nitrogen
Co-reporter:Ziwu Liu, Qianqian Shi, Rufan Zhang, Quande Wang, Guojun Kang, Feng Peng
Journal of Power Sources 2014 Volume 268() pp:171-175
Publication Date(Web):5 December 2014
DOI:10.1016/j.jpowsour.2014.06.036
•0.85% Pt supported on phosphorus-doped carbon nanotubes (Pt/P-CNTs) is designed.•Pt/P-CNTs exhibit a high activity for oxygen reduction reaction in acidic media.•The intrinsic activity and stability of Pt/P-CNTs are enhanced compared with Pt/CNTs.•The enhanced performances are due to the strong interaction between Pt and P-CNTs.•This strong Pt-support interaction is proven by experiment and theory calculations.To develop low-cost and efficient cathode electrocatalysts for fuel cells in acidic media, phosphorus-doped carbon nanotubes (P-CNTs) supported low Pt loading catalyst (0.85% Pt) is designed. The as-prepared Pt/P-CNTs exhibit significantly enhanced electrocatalytic oxygen reduction reaction (ORR) activity and long-term stability due to the stronger interaction between Pt and P-CNTs, which is proven by X-ray photoelectron spectroscopic analysis and density functional theory calculations. Moreover, the as-prepared Pt/P-CNTs also display much better tolerance to methanol crossover effects, showing a good potential application for future proton exchange membrane fuel cell devices.The as-prepared Pt/P-CNTs exhibit significantly enhanced electrocatalytic oxidation reduction reaction (ORR) activity, high onset potential and long-term stability due to the stronger interaction between Pt and P-CNTs, which was proven by XPS and DFT calculations.
Co-reporter:Siyuan Yang, Shengsen Zhang, Hongjuan Wang, Hao Yu, Yueping Fang and Feng Peng
RSC Advances 2014 vol. 4(Issue 81) pp:43024-43028
Publication Date(Web):28 Aug 2014
DOI:10.1039/C4RA07593E
Self-assembled mesoporous CuO nanospheres (CuO NSs) and hollow Cu2O microspheres (Cu2O MSs) were synthesized by a facile ethylene glycol–water solvothermal method without any surfactants. The formation and evolution of copper oxides were investigated by controlling the synthesis conditions. The as-prepared CuxO materials showed an excellent adsorption capability for the quick removal of Acid Orange 7 (AO7) dye in water.
Co-reporter:Biyu Peng, Shengsen Zhang, Siyuan Yang, Hongjuan Wang, Hao Yu, Shanqing Zhang, Feng Peng
Materials Research Bulletin 2014 56() pp: 19-24
Publication Date(Web):
DOI:10.1016/j.materresbull.2014.04.042
Co-reporter:Guoyu Zhong, Hongjuan Wang, Hao Yu, Feng Peng
Electrochemistry Communications 2014 40() pp: 5-8
Publication Date(Web):
DOI:10.1016/j.elecom.2013.12.017
Co-reporter:Shixia Liao;Yumei Chi;Dr. Hao Yu;Dr. Hongjuan Wang ;Dr. Feng Peng
ChemCatChem 2014 Volume 6( Issue 2) pp:555-560
Publication Date(Web):
DOI:10.1002/cctc.201300909
Abstract
In this study it is demonstrated that carbon nanotubes (CNTs) with doped nitrogen atoms in graphitic domains (NCNTs) can act as a new class of metal-free catalysts exhibiting excellent activity in the aerobic oxidation of cumene. We proved that NCNTs can promote the decomposition of hydroperoxide cumene with exceptionally high activity, resulting in strongly increased cumene conversion and extraordinarily high selectivity to acetophenone and 2-benzyl-2-propanol. The incorporation of nitrogen altered the surface electron structure of the CNTs and tuned the reactivity and selectivity. DFT calculations revealed that the remarkable improvement of catalytic performance of NCNTs is caused by the strong interaction between hydroperoxide cumene and the NCNTs. NCNTs also exhibited desirable recyclability after four cycling tests. This study not only provides a novel method for the cumene oxidation to high-value-added products at moderate reaction temperatures and oxygen atmospheric pressure, but also gives new insights into the effect of surface nitrogen doping on carbon-catalyzed liquid-phase oxidation of aromatic hydrocarbons.
Co-reporter:Junhui Yi, Shengsen Zhang, Hongjuan Wang, Hao Yu, Feng Peng
Materials Research Bulletin 2014 60() pp: 130-136
Publication Date(Web):
DOI:10.1016/j.materresbull.2014.08.028
Co-reporter:Shengsen Zhang, Shanqing Zhang, Biyu Peng, Hongjuan Wang, Hao Yu, Haihui Wang, Feng Peng
Electrochemistry Communications 2014 40() pp: 24-27
Publication Date(Web):
DOI:10.1016/j.elecom.2013.12.013
Co-reporter:Qianqian Shi, Feng Peng, Shixia Liao, Hongjuan Wang, Hao Yu, Ziwu Liu, Bingsen Zhang and Dangsheng Su
Journal of Materials Chemistry A 2013 vol. 1(Issue 47) pp:14853-14857
Publication Date(Web):04 Oct 2013
DOI:10.1039/C3TA12647A
Carbon materials have received an increasing amount of attention due to their low cost, long-term stability, and high electrocatalytic activity in catalyzing the cathodic oxygen reduction reaction (ORR). However, most of the carbon catalysts have exhibited their excellent activity only in alkaline media, which greatly hinders their practical application in polymer electrolyte membrane fuel cells (PEMFCs). In order to break the restriction of alkaline conditions, sulfur and nitrogen doped carbon nanotubes (SN-CNTs) were designed and successfully prepared via annealing of a mixture composed of nitrogen doped carbon nanotubes (N-CNTs) and sulfur. The result showed the as-prepared SN-CNTs have an enhanced ORR activity in both acidic and alkaline media compared with N doped CNTs (N-CNTs). This report also provides a new approach to explore low-cost electrocatalysts for practical fuel cell applications.
Co-reporter:Zhuangchai Lai, Feng Peng, Hongjuan Wang, Hao Yu, Shanqing Zhang and Huijun Zhao
Journal of Materials Chemistry A 2013 vol. 1(Issue 13) pp:4182-4185
Publication Date(Web):12 Feb 2013
DOI:10.1039/C3TA00188A
A facile and controllable hydrothermal approach is developed to synthesize rutile TiO2 single crystals with regulable (110), (111) and (001) facets without toxic capping agents. The normalized surface photoreactivity of the as-prepared TiO2 with (111) and (001) facets is approximately 5 times that of rutile TiO2 with majority (110) facets.
Co-reporter:Chunlin Chen, Jian Zhang, Bingsen Zhang, Changlin Yu, Feng Peng and Dangsheng Su
Chemical Communications 2013 vol. 49(Issue 74) pp:8151-8153
Publication Date(Web):22 May 2013
DOI:10.1039/C3CC41500G
Bulk nitrogen doping can efficiently improve the catalytic performance of carbon nanotubes (CNT) in oxidative dehydrogenation of propane (ODH). The graphitic nitrogen plays a determining role in enhancing their activity by speeding up the activation of oxygen and decreasing the overall activation energy of the reaction.
Co-reporter:Yonghai Cao, Xianyu Luo, Hao Yu, Feng Peng, Hongjuan Wang and Guoqing Ning
Catalysis Science & Technology 2013 vol. 3(Issue 10) pp:2654-2660
Publication Date(Web):28 Jun 2013
DOI:10.1039/C3CY00256J
The catalytic properties of sp2- and sp3-hybridized carbons, represented by graphene and diamond, in the selective oxidation of cyclohexane were investigated to understand the structure dependence of carbon materials in the reaction. sp2 carbons showed the higher activity than sp3 carbons. The highest activity was obtained over mesoporous graphene, a representative sp2-hybridized carbon, yielding a weight-normalized activity of 162.6 mmol g−1 h−1. The excellent performance of sp2 carbons was rationalized by their ability to catalyze the decomposition of peroxide intermediates, such as cyclohexyl hydroperoxide, which promoted the oxidative reaction to produce cyclohexanol and cyclohexanone.
Co-reporter:Shengsen Zhang, Biyu Peng, Siyuan Yang, Yueping Fang, Feng Peng
International Journal of Hydrogen Energy 2013 Volume 38(Issue 32) pp:13866-13871
Publication Date(Web):25 October 2013
DOI:10.1016/j.ijhydene.2013.08.081
•Cu2O/TiO2 nanotube arrays (Cu2O/TNA) are prepared by electrodeposition method.•The morphology of Cu2O nanoparticles on the TNA is controlled by electrodeposition potential.•Cu2O/TNA exhibits high visible-light-driven photocatalytic activity for H2 evolution.•The structure-dependent photoactivity of Cu2O/TNA for H2 evolution has been reported.The influence of the electrodeposition potential on the morphology of Cu2O/TiO2 nanotube arrays (Cu2O/TNA) and their visible-light-driven photocatalytic activity for hydrogen evolution have been investigated for the first time in this work. The photocatalytic hydrogen evolution rate of the as-prepared Cu2O/TNA at the deposition potential of −0.8 V was about 42.4 times that of the pure TNA under visible light irradiation. This work demonstrated a feasible and simple electrodeposition method to fabricate an effective and recyclable visible-light-driven photocatalyst for hydrogen evolution.The morphologies and photo-electrochemical performances of Cu2O/TiO2 nanotube arrays (Cu2O/TNA) were largely influenced by electrodeposition potential, a suitable structure for photocatalytic hydrogen production has been designed.
Co-reporter:Shengsen Zhang, Hongjuan Wang, Mingsang Yeung, Yueping Fang, Hao Yu, Feng Peng
International Journal of Hydrogen Energy 2013 Volume 38(Issue 18) pp:7241-7245
Publication Date(Web):18 June 2013
DOI:10.1016/j.ijhydene.2013.04.027
•Cu(OH)2 nanoparticles are loaded on the TiO2 nanotube arrays (TNAs).•The amount of Cu(OH)2 loaded on the arrays is controlled by the deposition times.•The H2-production yield of Cu(OH)2/TNAs is 20.3 times that of pure TNAs.•Cu(OH)2/TNAs catalyst shows excellent stability and reusability for H2-production.Cu(OH)2/TNAs photocatalyst was prepared by loading Cu(OH)2 nanoparticles on TiO2 nanotube arrays (TNAs) using a chemical bath deposition method. The amount of Cu(OH)2 loaded on the arrays was controlled by the repeated deposition times. The prepared catalyst was used to generate hydrogen under simulated solar light irradiation, and the results demonstrated that the hydrogen yield of Cu(OH)2/TNAs was 20.3 times that of the pure TNAs. Furthermore, the photocatalytic efficiency for hydrogen production decreased only 5.8% after five cycles, indicating that Cu(OH)2/TNAs photocatalyst showed excellent stability and reusability. This work presents an applicable and facile method to fabricate a highly active and stable photocatalyst for hydrogen production.
Co-reporter:Jin Luo; Feng Peng;Dr. Hao Yu;Dr. Hongjuan Wang;Dr. Wenxu Zheng
ChemCatChem 2013 Volume 5( Issue 6) pp:1578-1586
Publication Date(Web):
DOI:10.1002/cctc.201200603
Abstract
It was reported for the first time that carbon nanotubes (CNTs) as metal-free catalyst exhibited an excellent activity in the selective oxidation of ethylbenzene (EB) to acetophenone (AcPO) in the liquid-phase with oxygen as the oxidant. The reasonable mechanism responsible for the liquid-phase oxidation of EB on CNTs was proposed. The results demonstrated that the CNTs played an important role in the decomposition of 1-phenylethyl hydroperoxide (PEHP) and contributed to the production of AcPO, owing to π–π interactions between the radical species and peroxides and the graphene sheets of the CNTs. Surface carboxylic groups of the CNTs were unfavorable to EB oxidation. Adsorption energies of the radical species and peroxides on pristine and modified CNTs with carboxylic groups were calculated by DFT. These theoretical calculations were well consistent with the experimental results, and also supported the presented mechanistic pathway of EB oxidation on CNTs. This study not only presents a facile and effective alternative to cobalt-based catalysts for the selective oxidation of EB to AcPO but also gives new insight into the effect of surface structures on carbon-catalyzed reactions, and further pushes forward the research on carbon catalysis.
Co-reporter:Xixian Yang;Dr. Hongjuan Wang;Jing Li;Dr. Wenxu Zheng;Dr. Rong Xiang; Zikang Tang; Hao Yu; Feng Peng
Chemistry - A European Journal 2013 Volume 19( Issue 30) pp:9818-9824
Publication Date(Web):
DOI:10.1002/chem.201300676
Abstract
As some of the most interesting metal-free catalysts, carbon nanotubes (CNTs) and other carbon-based nanomaterials show great promise for some important chemical reactions, such as the selective oxidation of cyclohexane (C6H12). Due to the lack of fundamental understanding of carbon catalysis in liquid-phase reactions, we have sought to unravel the role of CNTs in the catalytic oxidation of C6H12 through a combination of kinetic analysis, in situ spectroscopy, and density functional theory. The catalytic effect of CNTs originates from a weak interaction between radicals and their graphene skeletons, which confines the radicals around their surfaces. This, in turn, enhances the electron-transfer catalysis of peroxides to yield the corresponding alcohol and ketone.
Co-reporter:Hongjuan Wang, Cheng Peng, Jiadao Zheng, Feng Peng, Hao Yu
Materials Research Bulletin 2013 48(9) pp: 3389-3393
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.05.015
Co-reporter:Zhuangchai Lai, Feng Peng, Yun Wang, Hongjuan Wang, Hao Yu, Porun Liu and Huijun Zhao
Journal of Materials Chemistry A 2012 vol. 22(Issue 45) pp:23906-23912
Publication Date(Web):25 Sep 2012
DOI:10.1039/C2JM34880B
A facile hydrothermal approach for synthesizing anatase TiO2 single crystals with wholly {100} and {001} facets under a reaction temperature as low as 100 °C is reported. NaBF4 and NaF are used as the facet control agents instead of HF, which are safer and much easier to use. By adjusting the reaction conditions, the lowest energy {101} facets can be completely eliminated. The anatase TiO2 with 45% {100} and 55% {001} facets exhibits a considerably higher specific surface photoreactivity than P25. The formation mechanism of the high surface energy facets is explored by XPS and DFT calculations. The results confirm that the reactions of the –OH groups on the surface of anatase TiO2 that are replaced by F atoms are exothermic and can lower the surface energy of {100} and {001} facets, indicating that anatase TiO2 with pure high energy facets can be prepared at temperatures as low as 100 °C with the existence of the surface lattice F. It is the first report that the surface lattice F generated in the reaction may stabilize and lead to the disappearance of the lowest surface energy {101} facet under low temperature.
Co-reporter:Xiaosong Zhou, Bei Jin, Liandi Li, Feng Peng, Hongjuan Wang, Hao Yu and Yueping Fang
Journal of Materials Chemistry A 2012 vol. 22(Issue 34) pp:17900-17905
Publication Date(Web):13 Jul 2012
DOI:10.1039/C2JM32686H
A carbon nitride/TiO2 nanotube array (CN/TNT) heterojunction photocatalyst with visible-light response was prepared by a simple electrochemical method. The photocatalyst was characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The photoelectrochemical properties and photocatalytic activities of the obtained-samples were systematically tested under visible light irradiation. The activity of heterojunction photocatalyst CN/TNTs is higher than that of TNTs. The obviously increased performance of CN/TNTs is ascribed mainly to enhancement of electron–hole separations both at the interface and in the semiconductors.
Co-reporter:Xiaosong Zhou, Feng Peng, Hongjuan Wang, Hao Yu and Yueping Fang
Chemical Communications 2012 vol. 48(Issue 4) pp:600-602
Publication Date(Web):24 Nov 2011
DOI:10.1039/C1CC15751E
Nanoscaled nitrogen doped anatase TiO2 with dominant (001) facets, which exhibited high photocatalytic activity and excellent photoelectrochemical properties under visible light irradiation, was successfully synthesized by solvothermal treatment of TiN in acidic NaBF4 solution for the first time.
Co-reporter:Xiaosong Zhou, Bei Jin, Shengsen Zhang, Hongjuan Wang, Hao Yu, Feng Peng
Electrochemistry Communications 2012 Volume 19() pp:127-130
Publication Date(Web):June 2012
DOI:10.1016/j.elecom.2012.03.020
Boron and phosphor co-doped TiO2 nanotube arrays (BP–TNTs) were prepared in an electrolyte containing triethyl borate and tributyl phosphate via an anodization process on a Ti sheet, and were characterized by the field-emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV–Vis diffusion reflectance spectroscopy. The photoelectrochemical properties and photocatalytic activities of obtained-samples were tested under visible light irradiation. The results showed that the photoelectrochemical and photocatalytic activities of B–TNTs, P–TNTs and BP–TNTs were higher than those of pure TiO2 nanotube arrays (TNTs). The synergistic effect of B and P co-doping was absent.Novel P- and B-codoped TiO2 nanotube arrays (TNTs) are designed and synthesized, which exhibit an improved visible light photocatalytic activity.Highlights► Novel P- and B-codoped TiO2 nanotube arrays (TNTs) are designed and synthesized. ► The effect of B and P content on photocurrent response under visible light is tested. ► B–TNTs, P–TNTs and BP–TNTs exhibit an improved visible light photocatalytic activity. ► The synergistic effect of B and P codoping on photoelectrochemical performance is absent.
Co-reporter:Ziwu Liu, Qianqian Shi, Feng Peng, Hongjuan Wang, Rufan Zhang, Hao Yu
Electrochemistry Communications 2012 Volume 16(Issue 1) pp:73-76
Publication Date(Web):March 2012
DOI:10.1016/j.elecom.2011.11.033
Phosphorus-doped multiwalled carbon nanotubes (P-MCNTs) were synthesized by thermolysis and employed as supports to prepare Pt/P-MCNTs catalyst for direct methanol fuel cells (DMFCs). Pt/P-MCNTs exhibited much higher electrocatalytic activity and longer-term stability for methanol oxidation than Pt/MCNTs in acidic medium, due to the higher dispersion and utilization rate and the improvement of intrinsic activity for methanol oxidation of Pt nanoparticles, indicating a highly potential application of Pt/P-MCNTs in DMFCs.Pt/P-MCNTs exhibited a much higher electrocatalytic activity for methanol oxidation than Pt/MCNTs, due to the formation of Pt particles with a smaller size and higher Pt utilization ratio and the improvement of Pt intrinsic activity for methanol oxidation.Highlights► Pt supported on phosphorus-doped multiwalled carbon nanotubes as an anode catalyst (Pt/P-MCNTs) is prepared. ► P-MCNTs can facilitate the formation of Pt particles with much smaller size than MCNTs. ► The electro-activity of Pt/P-MCNTs for methanol oxidation is 5 times that of Pt/MCNTs. ► Pt nanoparticles supported on P-MCNTs have much higher stability than those on MCNTs.
Co-reporter:Hongqing Chen, Hao Yu, Jichao Li, Feng Peng, and Hongjuan Wang
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 30) pp:10132-10139
Publication Date(Web):July 3, 2012
DOI:10.1021/ie300349s
Two types of flow distributors, that is, a jet-flow-splitter and a simplified constructal distributor, were designed to equalize the gaseous reagents in the inlet of a microreformer packed with catalyst supported on ceramic foam. The effects of type and geometry of distributors on flow, temperature distributions, and reaction performance over the catalyst during the autothermal reforming of ethanol were investigated experimentally and computationally. It was found that the jet flow splitter in the shape of cone or hemisphere can effectively equalize the flow distribution on the lower surface of catalyst, thereby improving the temperature distribution and performance of the microreformer. A microreformer with a hemisphere jet-flow-splitter in optimal geometry can convert 91% of ethanol with a selectivity to hydrogen of 74%, equivalent to yielding 3.3 mol of hydrogen per mol ethanol. Such a distribution device can be used to fabricate an efficient microreformer with simple structure for the hydrogen production orienting the portable fuel cell application.
Co-reporter:Shengsen Zhang;Chang Liu;Xiaolu Liu
Applied Microbiology and Biotechnology 2012 Volume 96( Issue 5) pp:1201-1207
Publication Date(Web):2012 December
DOI:10.1007/s00253-012-4233-7
In this work, we report the use of a non-toxic nanocrystal Cu2O-loaded TiO2 nanotube array (Cu2O/TNTs) film as high-performance visible-light bactericidal photocatalyst. The samples were characterized by field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet–visible diffusion reflection spectroscopy. This Cu2O/TNTs film photocatalyst is capable of complete inactivation of Escherichia coli in 5 × 107 colony-forming units/mL within a record short disinfection time of 20 min under visible-light irradiation. The average bactericidal percentage of the Cu2O/TNTs for E. coli under visible-light irradiation are 20 times and 6.6 times higher than those of TNTs under the same conditions and Cu2O/TNTs without light, respectively. This superior bactericidal performance is mainly attributed to the high ability to produce OH radicals by both photogenerated electron and hole of the prepared photocatalyst under visible light. The Cu2O/TNTs film photocatalyst makes it applicable to broad fields including drinking water disinfection.
Co-reporter:Xixian Yang;Dr. Hao Yu; Feng Peng;Dr. Hongjuan Wang
ChemSusChem 2012 Volume 5( Issue 7) pp:1213-1217
Publication Date(Web):
DOI:10.1002/cssc.201100807
Co-reporter:Zhiwei Yao, Xiaohong Zhang, Feng Peng, Hao Yu, Hongjuan Wang and Jian Yang
Journal of Materials Chemistry A 2011 vol. 21(Issue 19) pp:6898-6902
Publication Date(Web):31 Mar 2011
DOI:10.1039/C1JM10833F
MoN
nanoparticles in a size range around 50 nm were obtained on CNTs support via a novel carbothermal reduction nitridation (CRN). For the first time, a common (NH4)6Mo7O24·4H2O can be used as a Mo source to prepare MoN nanoparticles. A Mo-containing precursor was in a first step carburized and was reduced to a MoOxCy/Mo mixture. During further carbothermal nitridation this mixture-phase was shifted to the MoN phase through either a Mo2C or MoOxNy intermediate. Compared with the conventional NH3-temperature-programmed treatment (TPT) route that produced Mo nitride from MoO2 with rigorous heating method, the CRN route favored the formation of Mo nitride from easily nitridable MoOxCy/Mo, MoOxNy and Mo2C intermediates. The phase structure of the Mo nitride product was greatly dependent on nitridation reaction pathway. The NH3-TPT route yielded cubic Mo2N, while the CRN process produced hexagonal MoN.
Co-reporter:Xiaosong Zhou, Feng Peng, Hongjuan Wang, Hao Yu and Yueping Fang
Chemical Communications 2011 vol. 47(Issue 37) pp:10323-10325
Publication Date(Web):19 Aug 2011
DOI:10.1039/C1CC13862F
Novel carbon nitride polymer sensitized TiO2 nanotube arrays with high photocatalytic activity and photoelectrochemical response under visible light irradiation are prepared by electrodeposition.
Co-reporter:Xiaosong Zhou, Feng Peng, Hongjuan Wang, Hao Yu, Jian Yang
Electrochemistry Communications 2011 Volume 13(Issue 2) pp:121-124
Publication Date(Web):February 2011
DOI:10.1016/j.elecom.2010.11.030
B, N-codoped TiO2 nanotube arrays (BN-TNTs) were prepared in an electrolyte containing BF3 via an anodization process on a Ti sheet and subsequently annealed in ammonia ambient at 500 cu °C, and were characterized by the field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–Vis diffusion reflection spectroscopy (DRS). The highly-ordered vertically oriented nanotube arrays were obtained. The BN-TNTs exhibited more excellent photoelectrochemical properties and photocatalytic activities than those of TiO2 nanotube arrays (TNTs), B-doped TiO2 nanotube arrays (B-TNTs) and N-doped TiO2 nanotube arrays (N-TNTs) under UV–visible and visible light. The synergistic effects of B and N codoping were proven by photocatalytic and photoelectrochemical performances.
Co-reporter:Shengsen Zhang, Shanqing Zhang, Feng Peng, Haimin Zhang, Hongwei Liu, Huijun Zhao
Electrochemistry Communications 2011 Volume 13(Issue 8) pp:861-864
Publication Date(Web):August 2011
DOI:10.1016/j.elecom.2011.05.022
Nano-sized polyhedral crystalline Cu2O was evenly loaded throughout the structure of TiO2 nanotube arrays (TNTs) using an electrodeposition method, which resulted in a nanocomposite namely Cu2O/TNTs. The content of Cu2O loaded on the arrays was controlled by varying the electrodeposition charges. Under visible light, the photocurrent for water splitting and photocatalytic decolorization efficiency of dye Acid orange II (AO-II) of the Cu2O/TNTs obtained with the deposition charges of 500 mC were about 35 and 18 times that of TNTs, respectively. The polyhedral Cu2O/TNTs would be a promising material for solar energy conversion and organic pollutant degradation.The content and size of Cu2O loaded on the TiO2 nanotube arrays were controlled by the electrodeposition charges. The as-prepared Cu2O/TNTs-500 exhibited excellent photoelectrochemical property and photocatalytic activity under visible light.Research highlights►The polyhedral Cu2O nanocrystalline is evenly loaded on the TiO2 nanotube arrays(TNTs). ► The content and size of Cu2O loaded can be controlled by the electrodeposition charges. ► The Cu2O/TNTs exhibit an excellent photoelectrochemical property under visible light.
Co-reporter:Shengsen Zhang, Jingxia Qiu, Jisheng Han, Haimin Zhang, Porun Liu, Shanqing Zhang, Feng Peng, Huijun Zhao
Electrochemistry Communications 2011 Volume 13(Issue 11) pp:1151-1154
Publication Date(Web):November 2011
DOI:10.1016/j.elecom.2011.09.012
Hierarchically structured TiO2 (HST) films composed of top porous nanoparticle layer and underneath nanotube array layer are obtained by an anodization method on fluorine doped tin oxide surfaces. Compared with the TiO2 nanotube arrays photoanode on Ti substrate, the HST photoanode exhibits a higher photoelectrocatalytic activity towards the oxidation of water and organics (e.g., glucose).Hierarchically structured TiO2 (HST) films are obtained by an anodization method on floride doped tin oxide surfaces, which exhibit a higher photoelectrocatalytic activity towards the oxidation of water and organics (e.g., glucose).Highlights► Hierarchically structured TiO2 (HST) films are successfully fabricated by a one-step anodization method. ► The HST photoanode exhibits enhanced photoelectrocatalytic activity towards the oxidation of water and glucose. ► Electron pathways are well connected between the porous nanoparticle layer and the TiO2 nanotube arrays layer.
Co-reporter:Zhiwei Yao, Xiaohong Zhang, Feng Peng, Hao Yu, Hongjuan Wang, Jian Yang
International Journal of Hydrogen Energy 2011 Volume 36(Issue 3) pp:1955-1959
Publication Date(Web):February 2011
DOI:10.1016/j.ijhydene.2010.11.082
Novel alumina-supported cobalt nitride catalysts with Co loading ranging from 1 to 10 wt% prepared by NH3-temperature-programmed reaction were investigated as potential catalysts for preferential CO oxidation (PROX) in excess H2 at high temperatures. The formation of the Co4N phase was confirmed by a combination of XRD and XPS, and the Co 2p binding energies of Co4N reported previously were corrected to 798.2 ± 0.2 and 782.5 ± 0.2 eV. We observed that the catalytic activities of these nitrided Co/γ-Al2O3 catalysts were greatly related to their Co loadings. The nitrided 3 wt% Co/γ-Al2O3 catalyst showed the best PROX performance in temperature range of 200–220 °C, which was quite different from Co oxide precursor but was similar to Pt-group metals.Research highlights► Novel alumina-supported Co nitride catalysts are prepared by ammonolysis reaction. ► The nitrided 3 wt% Co/γ-Al2O3 catalyst shows excellent PROX performance at 200 °C ► The catalytic behavior of Co nitirde/γ-Al2O3 is similar to that of Pt-group metals.
Co-reporter:Xiaosong Zhou, Feng Peng, Hongjuan Wang, Hao Yu, Jian Yang
Journal of Solid State Chemistry 2011 Volume 184(Issue 1) pp:134-140
Publication Date(Web):January 2011
DOI:10.1016/j.jssc.2010.10.039
B,N-TiO2 photocatalysts were synthesized by boron doping firstly and subsequently nitrogen doping in NH3 at variable temperatures. The effects of the nitrogen doping temperature on the structure and photocatalytic activity of the B,N-codoped TiO2 were investigated. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectrum (DRS), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated with photocatalytic degradation of methyl orange dye (MO) under visible light and UV–visible light irradiation. The results suggested that the boron and nitrogen can be incorporated into the TiO2 lattice either interstitially or substitutionally or both, while the Ti–O–B–N structure plays a vital role in photocatalytic activity in visible light region. The optimal nitrogen doping temperature is 550 °C. Higher temperature may form many oxygen vacancies and Ti3+ species, resulting in the decrease of photocatalytic activity in visible light.Graphical abstractThe changes of photocatalytic activity of B,N-TiO2 with variable nitrogen doping temperatures are attributed to the transformation of surface structure and oxygen vacancies, and the Ti–O–B–N structure plays a vital role in photocatalytic activity under visible light irradiation.Research Highlights►B,N-TiO2 photocatalysts are synthesized by boron doping firstly and subsequently nitrogen doping in NH3 at variable temperatures. ►The boron and nitrogen can be incorporated into the TiO2 lattice either interstitially or substitutionally or both. ►The temperature of nitrogen doping affects the transformation of surface structure and oxygen vacancies. The ►Ti–O–B–N structure plays an important role in photocatalytic activity under visible light irradiation.
Co-reporter:Lei Huang, Feng Peng, Hongjuan Wang, Hao Yu, Wei Geng, Jian Yang, Shanqing Zhang, Huijun Zhao
Materials Chemistry and Physics 2011 Volume 130(1–2) pp:316-322
Publication Date(Web):17 October 2011
DOI:10.1016/j.matchemphys.2011.06.052
TiO2 nanotube (TNT) arrays loaded with octahedral Cu2O particles were successfully prepared by anodic oxidation followed with cathodic deposition. Annealing the TNT arrays before the cathodic deposition could effectively lower the electric resistance at the bottom of TNTs walls and then favor the deposition of octahedral Cu2O particles into TNT arrays. The effects of the applied reduction potential, the CuSO4 concentration, the pH value, the reaction temperature on the kinetics of cathode deposition and the Cu2O morphology were investigated. It was found that octahedral Cu2O particles were obtained under larger deposition current, while amorphous Cu2O were obtained under smaller current.Graphical abstractHighlights• Annealing the TNT arrays favors the deposition of octahedral Cu2O particles into TNT arrays. • The larger deposition-current leads to octahedral Cu2O particles. • The smaller deposition current leads to amorphous Cu2O. • Different types of Cu2O can be electrodeposited into or onto TNT arrays controllably.
Co-reporter:Xiaosong Zhou, Feng Peng, Hongjuan Wang, Hao Yu
Journal of Solid State Chemistry 2011 Volume 184(Issue 11) pp:3002-3007
Publication Date(Web):November 2011
DOI:10.1016/j.jssc.2011.09.017
Boron and nitrogen codoped TiO2 nanorods (BNTRs) were synthesized via two-step hydrothermal reactions using TiN as a starting material. The as-prepared samples were characterized by X-ray diffraction, field-emission scanning electron microscope (SEM), transmission electron microscopy and X-ray photoelectron spectroscopy techniques. The results showed that TiO2 nanorods with the diameter of approximately 50–100 nm and the length of several micrometers were doped by the interstitial N and B. The nanorods were firstly formed in the hydrothermal synthesis of nitrogen doped TiO2. The growing process of nanorods was observed by SEM and a most probable formation mechanism of the trititanate nanorods was proposed. The BNTRs showed a higher photocatalytic activity and a bigger photocurrent response than N–TiO2 nanorods under visible light irradiation.Graphical abstractBoron and nitrogen codoped TiO2 nanorods (BNTRs) were synthesized using TiN. The BNTRs showed a higher photocatalytic activity and a bigger photocurrent than N–TiO2 nanorods (NTRs) under visible light irradiation.Highlights► Novel B- and N-codoped TiO2 nanorods (BNTRs) are designed and synthesized. ► A most probable formation mechanism of the trititanate nanorods is proposed. ► The BNTRs show an outstanding photocurrent response under visible light. ► The BNTRs exhibit an improved visible light photocatalytic activity.
Co-reporter:Hongjuan Wang, Cheng Peng, Feng Peng, Hao Yu, Jian Yang
Materials Science and Engineering: B 2011 Volume 176(Issue 14) pp:1073-1078
Publication Date(Web):25 August 2011
DOI:10.1016/j.mseb.2011.05.043
A nanocomposite of manganese dioxide coated on the carbon nanotubes (MnO2/CNTs) was synthesized by a facile direct redox reaction between potassium permanganate and carbon nanotubes without any other oxidant or reductant addition. The morphology, microstructure and crystalline form of this MnO2/CNT nanocomposite were characterized by scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrochemical properties are characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge (GCD). The results show that the facile prepared MnO2/CNTs nanocomposite shows specific capacitance of 162.2 F g−1 at the current density of 0.2 A g−1 and excellent charge/discharge property with 90% of its specific capacitance kept after 2000 cycles at the current density of 5 A g−1.Highlights► MnO2/CNTs are prepared by direct redox reaction between KMnO4 and carbon nanotubes. ► This preparation method is a simple and green without any other additives. ► MnO2/CNTs show specific capacitance of 162.2 F g−1 at the current density of 0.2 A g−1. ► MnO2/CNTs exhibit excellent charge–discharge property.
Co-reporter:Zhiwei Yao, Zhuangchai Lai, Xiaohong Zhang, Feng Peng, Hao Yu, Hongjuan Wang
Materials Research Bulletin 2011 46(11) pp: 1938-1941
Publication Date(Web):
DOI:10.1016/j.materresbull.2011.07.023
Co-reporter:Dr. Zi-Wu Liu; Feng Peng;Dr. Hong-Juan Wang;Dr. Hao Yu;Dr. Wen-Xu Zheng; Jian Yang
Angewandte Chemie 2011 Volume 123( Issue 14) pp:3315-3319
Publication Date(Web):
DOI:10.1002/ange.201006768
Co-reporter: Hao Yu; Feng Peng;Jun Tan;Xiaowei Hu; Hongjuan Wang; Jian Yang; Wenxu Zheng
Angewandte Chemie 2011 Volume 123( Issue 17) pp:4064-4068
Publication Date(Web):
DOI:10.1002/ange.201007932
Co-reporter:Dr. Zi-Wu Liu; Feng Peng;Dr. Hong-Juan Wang;Dr. Hao Yu;Dr. Wen-Xu Zheng; Jian Yang
Angewandte Chemie International Edition 2011 Volume 50( Issue 14) pp:3257-3261
Publication Date(Web):
DOI:10.1002/anie.201006768
Co-reporter: Hao Yu; Feng Peng;Jun Tan;Xiaowei Hu; Hongjuan Wang; Jian Yang; Wenxu Zheng
Angewandte Chemie International Edition 2011 Volume 50( Issue 17) pp:3978-3982
Publication Date(Web):
DOI:10.1002/anie.201007932
Co-reporter:Xiaosong Zhou, Feng Peng, Hongjuan Wang, Hao Yu, Jian Yang
Materials Research Bulletin 2011 46(6) pp: 840-844
Publication Date(Web):
DOI:10.1016/j.materresbull.2011.02.029
Co-reporter:Chunmei Zhou, Feng Peng, Hongjuan Wang, Hao Yu, Cheng Peng, Jian Yang
Electrochemistry Communications 2010 Volume 12(Issue 9) pp:1210-1213
Publication Date(Web):September 2010
DOI:10.1016/j.elecom.2010.06.021
Manganese dioxide was coated on multiwall carbon nanotubes-supported PtRu particles to prepare the MnO2/PtRu/CNT catalyst by a facile oxidation–reduction method. The prepared catalyst showed a high stability for electrocatalytic oxidation of methanol. After 2000 potential cycles, 55% activity still remained for MnO2/PtRu/CNT catalyst, while only 30% activity remained for PtRu/CNT, which indicated that the electrochemical stability of MnO2/PtRu/CNTs was improved significantly. MnO2 in MnO2/PtRu/CNTs prevented the dissolution of PtRu particles as well as the corrosion of the CNT supports, resulting in the improvement of the stability and activity.
Co-reporter:Lei Huang, Feng Peng, Hao Yu, Hongjuan Wang, Jian Yang, Zhong Li
Materials Research Bulletin 2010 45(2) pp: 200-204
Publication Date(Web):
DOI:10.1016/j.materresbull.2009.09.018
Co-reporter:Hao Yu, Xiaobo Fu, Chunmei Zhou, Feng Peng, Hongjuan Wang and Jian Yang
Chemical Communications 2009 (Issue 17) pp:2408-2410
Publication Date(Web):14 Mar 2009
DOI:10.1039/B820063G
The activity of RuO2·xH2O/CNT for benzyl alcoholoxidation can be predicted by the specific capacitance (SC) of RuO2, suggesting that highly active RuO2 nanocatalysts are also good supercapacitor materials with SC high up to 1500 F gRuO2−1.
Co-reporter:Feng Peng, Chunlin Chen, Hao Yu, Hongjuan Wang, Jian Yang
Materials Chemistry and Physics 2009 Volume 116(Issue 1) pp:294-299
Publication Date(Web):15 July 2009
DOI:10.1016/j.matchemphys.2009.03.031
NaxBayBiO3·nH2O (NBBO) has been prepared using a commercial NaBiO3·nH2O (NBO) as a starting material with a hydrothermal iron-exchange reaction. As-synthesized samples were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible light (UV–vis) absorbance spectra, thermogravimetry-differential scanning calorimetry (TG-DSC) and X-ray photoelectron spectroscopy (XPS) techniques. The photooxidation decomposition of phenol over NBBO has been carried out under visible-light irradiation (λ > 400 nm). The result revealed that the NBBO showed considerable photooxidation activity for phenol degradation in the range of visible light. The result of reusability indicated the structure of NBBO was instable, which was changed to Bi2O2CO3 in the photooxidation process, although photooxidation activity kept high in three runs. This study has provided useful information for the development of new bismuthate photocatalyst with higher photoactivity under visible-light irradiation.
Co-reporter:Lei Huang, Feng Peng, Hao Yu, Hongjuan Wang
Solid State Sciences 2009 Volume 11(Issue 1) pp:129-138
Publication Date(Web):January 2009
DOI:10.1016/j.solidstatesciences.2008.04.013
Cuprous oxide (Cu2O) nanoparticles and microparticles have been prepared by liquid phase chemical synthesis. The samples were characterized by means of SEM, XRD, UV/DRS and XPS. It was presented that as-prepared Cu2O nanoparticles are substantially stable in ambient atmosphere and the Cu+ as main state exists on the surface of Cu2O nanoparticles. As-prepared Cu2O microparticles can exist stably as a Cu2O/CuO core/shell structure; and the Cu2+ as main state exists on the surface of Cu2O microparticles. The behaviors of adsorption, photocatalysis and photocorrosion of Cu2O particles with different sizes were investigated in detail. The results show that Cu2O nanoparticles are very easy to photocorrosion during the photocatalytic reaction, which cannot be used as photocatalyst directly to degrade organic compound, although as-prepared Cu2O nanoparticles exhibit special property of adsorption. Cu2O microparticles have a higher photocatalytic activity than Cu2O nanoparticles because of its slower photocorrosion rate, although Cu2O microparticles have much lower adsorption capacity than Cu2O nanoparticles. The mechanisms of photocatalysis and photocorrosion for Cu2O under visible light were also discussed. Cu2O microparticles have a higher photocatalytic activity than Cu2O nanoparticles because of its slower photocorrosion rate, although Cu2O microparticles have much lower adsorption capacity than Cu2O nanoparticles.
Co-reporter:Chunmei Zhou, Hongjuan Wang, Feng Peng, Jiahua Liang, Hao Yu and Jian Yang
Langmuir 2009 Volume 25(Issue 13) pp:7711-7717
Publication Date(Web):April 29, 2009
DOI:10.1021/la900250w
Pt/MnO2/carbon nanotube (CNT) and PtRu/MnO2/CNT nanocomposites were synthesized by successively loading hydrous MnO2 and Pt (or PtRu alloy) nanoparticles on CNTs and were used as anodic catalysts for direct methanol fuel cells (DMFCs). The existence of MnO2 on the surface of CNTs effectively increases the proton conductivity of the catalyst, which then could remarkably improve the performance of the catalyst in methanol electro-oxidation. As a result, Pt/MnO2/CNTs show higher electrochemical active surface area and better methanol electro-oxidation activity, compared with Pt/CNTs. As PtRu alloy nanoparticles were deposited on the surface of MnO2/CNTs instead of Pt, the PtRu/MnO2/CNT catalyst shows not only excellent electro-oxidation activity to methanol with forward anodic peak current density of 901 A/gPt but also good CO oxidation ability with lower preadsorbed CO oxidation onset potential (0.33 V vs Ag/AgCl) and peak potential (0.49 V vs Ag/AgCl) at room temperature.
Co-reporter:Hao Yu, Yuguang Jin, Zhili Li, Feng Peng, Hongjuan Wang
Journal of Solid State Chemistry 2008 Volume 181(Issue 3) pp:432-438
Publication Date(Web):March 2008
DOI:10.1016/j.jssc.2007.12.017
Single-walled carbon nanotubes (SWCNTs) were treated with sulfuric acid at 300 °C to synthesize sulfonated SWCNTs (s-SWCNTs), which were characterized by electron microscopy, infrared, Raman and X-ray photoelectron spectroscopy, and thermo analysis. Compared with activated carbon, more sulfonic acid groups can be introduced onto the surfaces of SWCNTs. The high degree (∼20 wt%) of surface sulfonation led to hydrophilic sidewalls that allows the SWCNTs to be uniformly dispersed in water and organic solvents. The high surface acidity of s-SWCNTs was demonstrated by NH3 temperature-programmed desorption technique and tested by an acetic acid esterification reaction catalyzed by s-SWCNTs. The results show that the water-dispersive s-SWCNTs are an excellent solid acid catalyst and demonstrate the potential of SWCNTs in catalysis applications.Sulfonated SWCNTs with 20 wt% −SO2OH groups were prepared by a high-temperature H2SO4 process, which transformed the hydrophobic surface of pristine SWCNTs to a hydrophilic surface and provided an excellent performance as solid acid catalyst.
Co-reporter:Feng Peng, Lingfeng Cai, Hao Yu, Hongjuan Wang, Jian Yang
Journal of Solid State Chemistry 2008 Volume 181(Issue 1) pp:130-136
Publication Date(Web):January 2008
DOI:10.1016/j.jssc.2007.11.012
Both substitutional and interstitial nitrogen-doped titanium dioxides (N-TiO2) were prepared. Their surface states were clarified by XPS spectra of N 1s, O 1s and Ti 2p. The results of photocatalysis show that both substitutional and interstitial N impurities greatly enhance the photoactivity of TiO2 in visible light. Moreover, the visible light activity of interstitial N-doped TiO2 is higher than that of substitutional N-doped TiO2. The microwave synthesis presented in this paper is a promising and practical method to produce interstitial nitrogen-doped photocatalysts with high visible light activity.Both substitutional and interstitial N impurities can enhance the photoactivity of TiO2 in visible light; moreover, the visible light activity of interstitial N-doped TiO2 is higher than that of substitutional N-doped TiO2.
Co-reporter:Feng Peng, Lingfeng Cai, Lei Huang, Hao Yu, Hongjuan Wang
Journal of Physics and Chemistry of Solids 2008 Volume 69(Issue 7) pp:1657-1664
Publication Date(Web):July 2008
DOI:10.1016/j.jpcs.2007.12.003
Nitrogen-doped TiO2 (N-TiO2) nanoparticles have been successfully prepared via a direct and simple hydrothermal reaction of a commercial Degussa P25 with triethanol amine as solvent and nitrogen source. As-prepared N-TiO2 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible light (UV–vis) absorption spectra, electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS) techniques. The results confirm that hydrothermal reaction is an effective way to incorporate nitrogen into the TiO2 lattice, especially nitrogen substitute for titanium. The nitrogen concentration in TiO2 can be as high as 21% (molar ratio), which is described as Ti1−yO2−xNx+y (in this paper, x=0.36, y=0.27, i.e., Ti0.73O1.64N0.63). The chemical statuses of N have been assigned to N–Ti–O and O–N–O in the TiO2 lattice as identified by XPS. Photocatalytic degradation of methyl orange has been carried out in both UV–vis (simulated solar light) and the visible region (λ>400 nm). N-TiO2 exhibits higher activity than the Degussa P25 TiO2 photocatalyst, particularly under visible-light irradiation. This study has developed a promising and practical pathway to new nitrogen-doped photocatalysts.
Co-reporter:Hao Yu ; Kai Zeng ; Xiaobo Fu ; Yan Zhang ; Feng Peng ; Hongjuan Wang ;Jian Yang
The Journal of Physical Chemistry C 2008 Volume 112(Issue 31) pp:11875-11880
Publication Date(Web):July 16, 2008
DOI:10.1021/jp804003g
Highly dispersed ruthenium oxide clusters were synthesized on carbon nanotubes (CNTs) to form RuO2·xH2O/CNT catalyst by a homogeneous oxidation precipitation method. Methanol oxidation was carried out on RuO2·xH2O/CNT at low temperatures for the production of diverse oxygenous products, such as methyl formate (MF) and dimethoxymethane (DMM). Unprecedented conversion rate of methanol, high up to 545 molMeOH (mol Rusurface)−1 h−1, was observed at 120 °C. The effect of structural water in RuO2 domains on the performances of the methanol oxidation reaction was investigated by annealing them in N2 at elevated temperatures. The dehydration of RuO2 clusters decreased the oxidation ability and changed the selectivity patterns. It was suggested that the behaviors of RuO2 during the annealing process may be strongly influenced by the interaction between RuO2 and CNTs.
Co-reporter:H.J. Wang, A.L. Zhou, F. Peng, H. Yu, L.F. Chen
Materials Science and Engineering: A 2007 Volume 466(1–2) pp:201-206
Publication Date(Web):25 September 2007
DOI:10.1016/j.msea.2007.02.097
Multiwalled carbon nanotubes (MWCNTs) were acidified by concentrated nitric acid and were employed as adsorbent to study the adsorption characteristic for Pb(II) from aqueous solution. The results show that adsorption capacity of MWCNTs treated by concentrated nitric acid can be greatly enhanced. The adsorption of acidified MWCNTs to Pb(II) fits to the Langmuir model. The larger adsorption capacity of acidified MWCNTs for Pb(II) is mainly due to the oxygenous functional groups formed on the surface of acidified MWCNTs which can react with Pb(II) to form salt or complex deposited on the surface of MWCNTs. The equilibrium time of adsorption for acidified MWCNTs to Pb(II) is about 20 min, which is much shorter than that of activated carbon (about 120 min). The regeneration performance for the first time was studied, it is showed that the Pb(II) can be easily regenerated from acidified MWCNTs by adjusting the solution to pH 2.
Co-reporter:Feng Peng;Hancai Zhu;Hongjuan Wang;Hao Yu
Korean Journal of Chemical Engineering 2007 Volume 24( Issue 6) pp:1022-1026
Publication Date(Web):2007 November
DOI:10.1007/s11814-007-0114-7
ZnO was prepared rapidly by microwave heating method. The results of scanning electron microscopy show that the leaflike ZnO is composed of self-assembled ZnO particles of 30–50 nm. Ag-sensitized ZnO composite was prepared by UV-photoreduction and glycol reduction, respectively. The composite was characterized by means of scanning electron microscopy, X-ray diffraction and photoluminescence. The ZnO and Ag/ZnO prepared were applied in photocatalytic degradation of phenol and methyl orange as model of organic pollutant in water under simulated solar light. The results show that Ag doping in both methods of UV-photoreduction and glycol reduction can remarkably improve the photocatalytic activity of ZnO under simulated solar light. The utilization ratio of Ag in glycol reduction is high and the optimum content of Ag in Ag/ZnO composite is only 1.33%. Therefore, the glycol reduction is a novel and excellent method for preparing Ag-sensitized ZnO composite with high photocatalytic activity.
Co-reporter:Yongli Zhang, Feng Peng, Yanbo Zhou
Chinese Journal of Chemical Engineering (September 2016) Volume 24(Issue 9) pp:1171-1177
Publication Date(Web):1 September 2016
DOI:10.1016/j.cjche.2016.02.007
A Cu–Fe–La/γ-Al2O3 (CFLA) catalyst was prepared by the excessive impregnation method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results indicate that the catalyst contained mostly Cu2 +, Fe3 +, and La3 + and a small amount of Cu+, Fe2 +, and La. The active components were uniformly distributed in the catalyst, and the particle size of the components was approximately 7.5 nm. The CFLA catalyst was used for the treatment of methyl orange (MO) solution by catalytic wet air oxidation (CWAO), and it exhibited a high catalytic activity. The catalytic reaction involved variable valence states of metals and free-radical reaction mechanism. The CWAO reaction of MO solution was fitted by a segmented first-order dynamic model, and the rapid reaction apparent activation energy was 13.9 kJ·mol− 1.The species O2−, H2O2, and HO existed in the MO reaction system for CWAO over the CFLA catalyst, and O2− exhibited the strongest activity. H2O2 exhibited the centered effect, whereas HO exhibited the weakest effect.The variable valence states of Cu, Fe, and La endow the CFLA catalyst with excellent electron-transfer properties and catalytic oxidation activity. The low-valence metals capture O2 to form O2− oxidative species, moreover, O2− combines with H+ in the solution, thus affording some stronger oxidative species such as H2O2, which oxidize organic matters into smaller molecules such as CO2, H2O, and other small molecule organic matters.Download full-size image
Co-reporter:Ziwu Liu, Feng Peng, Hongjuan Wang, Hao Yu, ... Xianyong Wei
Journal of Natural Gas Chemistry (May 2012) Volume 21(Issue 3) pp:257-264
Publication Date(Web):1 May 2012
DOI:10.1016/S1003-9953(11)60362-9
Phosphorus-doped carbon nanospheres without any metal residues were synthesized and characterized. The results revealed that the doping phosphorus atoms could significantly improve the electrocatalytic activity of graphitic carbon for the oxygen-reduction reaction (ORR) both in acidic and alkaline media, and the materials exhibited high electrocatalytic activity, long-term stability, and excellent tolerance to crossover effects especially in alkaline media. Quantum mechanics calculations with the density functional theory demonstrated that the changes in charge density and energetic characteristics of frontier orbitals for the P-doped graphene sheet could facilitate the ORR.
Co-reporter:Hongqing Chen, Hao Yu, Yong Tang, Minqiang Pan, ... Jian Yang
Journal of Natural Gas Chemistry (June 2009) Volume 18(Issue 2) pp:191-198
Publication Date(Web):1 June 2009
DOI:10.1016/S1003-9953(08)60106-1
Hydrogen was produced over noble metal (Ir, Ru, Rh, Pd) catalysts supported on various oxides, including γ-Al2O3, CeO2, ZrO2 and La2O3, via the autothermal reforming reaction of ethanol (ATRE) and oxidative reforming reaction of ethanol (OSRE). The conversion of ethanol and selectivites for hydrogen and byproducts such as methane, ethylene and acetaldehyde were studied. It was found that lanthana alone possessed considerable activity for the ATRE reaction, which could be used as a functional support for ATRE catalysts. It was demonstrated that Ir/La2O3 prevented the formation of methane, and Rh/La2O3 encumbered the production of ethylene and acetaldehyde. ATRE reaction was carried out over La2O3-supported catalysts (Ir/La2O3) with good stability on stream, high conversion, and excellent hydrogen selectivity approaching thermodynamic limit under autothermal condition. Typically, 3.4 H2 molecules can be extracted from a pair of ethanol and water molecules over Ir(5wt%)/La2O3. The results presented in this paper indicate that Ir/La2O3 can be used as a promising catalyst for hydrogen production via ATRE reaction from renewable ethanol.
Co-reporter:Hao Yu, Zhili Li, Cheng Zhang, Feng Peng, Hongjuan Wang
Journal of Natural Gas Chemistry (December 2007) Volume 16(Issue 4) pp:382-388
Publication Date(Web):1 December 2007
DOI:10.1016/S1003-9953(08)60008-0
The effects of additives containing iron or nickel during chemical vapor deposition (CVD) on the growth of carbon nanotubes (CNTs) by methane decomposition on Mo/MgO catalyst were investigated. Ferrocene and nickel nitrate were introduced as deactivation inhibitors by in-situ evaporation during CVD. The precisely controlled in-situ introduction of these inhibitors increased the surface renewal of catalyst, and therefore prevented the catalyst from deactivation. Using this method, aligned multi-walled CNTs with parallel mesopores can be produced on a large scale.
Co-reporter:Yonghai Cao, Hao Yu, Hongjuan Wang, Feng Peng
Catalysis Communications (5 January 2017) Volume 88() pp:99-103
Publication Date(Web):5 January 2017
DOI:10.1016/j.catcom.2016.10.002
•Solvents affect the oxidation of cyclohexene catalyzed by N-doped CNTs.•The higher polarity is beneficial for the activity in aliphatic solvents.•Aromatic solvents are less reactive due to the competitive adsorption.•A modest solvent basicity is required for high reactivity.•2-cyclohexen-1-one selectivity slightly increases with solvent polarity.A wide spectrum of, up to 22, organic solvents, including aprotic/protic aliphatics/aromatics, was studied to achieve a comprehensive understanding to the solvent effect on the cyclohexene oxidation. It was found that the catalytic activity was significantly influenced by the viscosity, polarity and basicity of solvents in this reaction. Among these solvents, the polar aprotic aliphatic solvents displayed higher catalytic reactivities than other types of solvents. A volcano curve was found describing the dependence of activity on solvent basicity because of the suitable stability of intermediates. Among the solvents investigated, acetonitrile afforded the highest activity and selectivity of 2-cyclohexen-1-one, because of a good compromise between strong polarity and moderate basicity.Download high-res image (64KB)Download full-size image
Co-reporter:Hongqing Chen, Hao Yu, Feng Peng, Hongjuan Wang, Jian Yang, Minqiang Pan
Journal of Catalysis (5 February 2010) Volume 269(Issue 2) pp:281-290
Publication Date(Web):5 February 2010
DOI:10.1016/j.jcat.2009.11.010
La2O3-supported Ir catalyst was prepared by wetness impregnation method for the oxidative steam reforming of ethanol (OSRE). Fresh, reduced, and used catalysts were characterized by N2 adsorption, H2 chemisorption, XRD, FT-IR, TEM, and XPS. La2O3 would transform into hexagonal La2O2CO3 during OSRE, which suppress coking effectively. Reduced Ir metal can interplay with La2O2CO3 to form Ir-doped La2O2CO3. It dynamically forms and decomposes to release active Ir nanoparticles, thereby preventing the catalyst from sintering and affording high dispersion of Ir/La2O3 catalysts at elevated temperatures. By introducing ultrasonic-assisted impregnation method during the preparation of a catalyst, the surface Ir concentration was significantly improved, while the in situ dispersion effect inhibited Ir from sintering. The Ir/La2O3 catalyst prepared by the ultrasonic-assisted impregnation method is highly active and stable for the OSRE reaction, in which the Ir crystallite size was maintained at 3.2 nm after 100 h on stream at 650 °C and metal loading was high up to 9 wt%.Ir nanoparticles are in situ formed and dispersed over La2O2CO3-II through the strong interaction between metal and support during the course of oxidative steam reforming of ethanol.Download high-res image (101KB)Download full-size image
Co-reporter:Ziwu Liu, Feng Peng, Hongjuan Wang, Hao Yu, Chunlin Chen, Qianqian Shi
Catalysis Communications (5 December 2012) Volume 29() pp:11-14
Publication Date(Web):5 December 2012
DOI:10.1016/j.catcom.2012.09.016
The low-content deposition of Pt on the working electrode during the electrochemical test showed high activity for oxygen reduction reaction (ORR) and much low activity for methanol oxidation reaction (MOR), indicating that there exists a difference in the ORR and MOR on the surface of few Pt nanoparticles . Based on this difference, we designed and prepared the Pt/carbon nanotube catalyst with ca. 0.86 wt.% Pt, which exhibited high ORR activity and well tolerance to methanol in acidic media, showing a good potential application for a future acidic direct methanol fuel cell device.Pt/MCNT catalyst with ultra-low Pt loading exhibits high oxygen reduction reaction (ORR) activity and well tolerance to methanol in acidic media.Download full-size imageHighlights► The dissolution of the counter electrode Pt in acidic media is tested quantitatively. ► Activity difference of Pt for oxygen reduction (ORR) and methanol oxidation is found. ► Pt/carbon nanotube catalyst(Pt/MCNT) with low Pt loading is designed and prepared. ► As-prepared Pt/MCNT exhibits high ORR activity and well tolerance to methanol.
Co-reporter:Shengsen Zhang, Feng Peng, Hongjuan Wang, Hao Yu, Shanqing Zhang, Jian Yang, Huijun Zhao
Catalysis Communications (31 March 2011) Volume 12(Issue 8) pp:689-693
Publication Date(Web):31 March 2011
DOI:10.1016/j.catcom.2011.01.001
Ag nanoparticles loaded N-doped TiO2 nanotube arrays (Ag/N-TNTs) were successfully fabricated by an electrodeposition method. The Ag/N-TNTs were characterized using field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffusion reflection spectroscopy (UV–vis DRS). The average photocurrent density and the photocatalytic degradation efficiency of the Ag/N-TNTs obtained for the degradation of Acid Orange II（AO-II）are 6 times and 6.8 times higher than those of annealed TiO2 nanotube arrays (A-TNTs), respectively. This bestows the Ag/N-TNTs as a promising photocatalytic material for organic pollutant degradation under visible light.Download full-size imageResearch Highlights► Ag/N-TNTs are successfully fabricated by an electrodeposition method. ► The integration of N and Ag can synergistically improve the photocatalytic property. ► The average photocurrent density of the Ag/N-TNTs is 6 times that of the TNTs.
Co-reporter:Ziwu Liu, Feng Peng, Hongjuan Wang, Hao Yu, Jun Tan, Lili Zhu
Catalysis Communications (30 November 2011) Volume 16(Issue 1) pp:35-38
Publication Date(Web):30 November 2011
DOI:10.1016/j.catcom.2011.08.038
Phosphorus-doped multiwalled carbon nanotubes (MCNTs) were synthesized by the thermolysis and characterized by electron microscopy and microanalysis technique and evaluated with electrochemical methods. The results revealed that carbon nanotube length became shorter, the tube diameters increased and the yield of MCNTs reduced gradually with the increase of the concentration of triphenylphosphine in toluene solution, and the tube diameters increased with the increase of the synthesis temperature. Moreover, the phosphorus doping significantly improved the electrocatalytic activity of carbon nanotubes for the oxygen-reduction reaction in alkaline media, and the carbon nanotubes doped with small amounts of phosphorus exhibited higher electrocatalytic activity and stability than Pt/C catalyst.P-doped MCNTs synthesized by thermolysis of toluene solution containing ferrocene and TPP, showed much higher electrocatalytic activity (3, 3′) for ORR in alkaline electrolyte solution than Pt–C/GC (1, 1′) and MCNTs (2, 2′) before (solid curves) and after (dotted curves) continuous potential cycling sweep for 5 days.Download full-size imageHighlights► Phosphorus-doped multiwalled carbon nanotubes (P-MCNTs) are prepared by thermolysis. ► Phosphorus doping significantly improves the oxygen-reduction activity of MCNTs. ► P-MCNTs exhibit higher electrocatalytic activity and stability than Pt/C catalyst.
Co-reporter:Hongqing Chen, Hao Yu, Yong Tang, Minqiang Pan, Feng Peng, Hongjuan Wang, Jian Yang
Applied Catalysis A: General (25 March 2008) Volume 337(Issue 2) pp:155-162
Publication Date(Web):25 March 2008
DOI:10.1016/j.apcata.2007.12.009
Co-reporter:Shixia Liao, Feng Peng, Hao Yu, Hongjuan Wang
Applied Catalysis A: General (20 May 2014) Volume 478() pp:
Publication Date(Web):20 May 2014
DOI:10.1016/j.apcata.2014.03.024
•Carbon nanotubes (CNTs) exhibits high activity for cumene to cumene hydroperoxide.•Cumene oxidation catalyzed by CNTs is proved a radical-involved reaction.•The surface functional groups and defects are unfavorable for the catalytic activity.•CNTs as a metal-free catalyst for the liquid-phase oxidation displays good stability.The effective oxidation reaction system using the commercial carbon nanotubes (CNTs) as catalysts for the liquid aerobic oxidation of cumene to cumene hydroperoxide (CHP) under low temperature is reported in this paper. Several reaction parameters, including the temperature, catalyst content, oxygen flow rate and reaction time were carefully studied. Under optimal conditions, cumene conversion of 24.1% with CHP selectivity of 88.4%, close to that of metal catalyst, was obtained. Cumene oxidation catalyzed by CNTs was proved a radical-involved reaction, and the outstanding catalytic performance was attributed to CHP decomposition catalyzed by CNTs to produce free radicals. Oxygenated functional groups on the surface of catalyst showed a negative effect on cumene oxidation due to the localization of electrons after the introducing of defects and oxygenated functional groups. CNTs as catalysts also showed desirable recyclability after five cycling tests. This study not only provides an applicable method for selective oxidation of cumene to CHP, but also gives some useful information on catalytic role of CNTs-catalyzed liquid-phase oxidation reactions of aromatic hydrocarbons.The commercial carbon nanotubes (CNTs) exhibited high activity and good stability for the liquid aerobic oxidation of cumene to cumene hydroperoxide (CHP) under low temperature.Download high-res image (169KB)Download full-size image
Co-reporter:Junhui Yi, Lingling Huang, Hongjuan Wang, Hao Yu, Feng Peng
Journal of Hazardous Materials (2 March 2015) Volume 284() pp:207-214
Publication Date(Web):2 March 2015
DOI:10.1016/j.jhazmat.2014.11.020
•TiO2 nanobelts (NBs) are grown in-situ on the Ti foil at 150 °C in a KOH solution.•AgI/TiO2 NBs monolithic catalyst is prepared by a simple method.•AgI/TiO2 NBs exhibit high visible-light photocatalytic activity for acid orange II degradation.•AgI/TiO2 NBs have an advantage over the drawback encountered with powder suspension.AgI nanoparticles (NPs) have been decorated on the TiO2 nanobelts (NBs) immobilized on a metal Ti substrate by a simple impregnating-precipitation method. The as-achieved AgI/TiO2 monolithic catalyst exhibits a high and stable visible photocatalytic activity toward acid orange II (AO-II) degradation, which is attributed to the suitable energy band match of AgI NPs and TiO2 NBs, leading to the efficient transfer of photo-generated electrons. In addition, it was found that O2− radicals and h+ are the main reactive species for the degradation of AO-II under visible light irradiation. A reasonable photocatalytic mechanism of AgI/TiO2 photocatalyst toward AO-II degradation was discussed. This monolithic catalyst provides an advantage over the drawback encountered with powder suspension.Download full-size imageAgI NPs supported on TiO2 NBs grown on the Ti foil as a monolithic catalyst exhibited excellent visible-light-driven photocatalytic activity, recyclability, and stability for AO-II degradation.
Co-reporter:Hongqing Chen, Hao Yu, Feng Peng, Guangxing Yang, Hongjuan Wang, Jian Yang, Yong Tang
Chemical Engineering Journal (15 May 2010) Volume 160(Issue 1) pp:333-339
Publication Date(Web):15 May 2010
DOI:10.1016/j.cej.2010.03.054
LaMnO3, LaFeO3, LaCoO3 and LaNiO3 perovskite oxides were prepared using combustion method for autothermal reforming of ethanol (ATRE). Fresh, reduced and used catalysts were characterized by XRD, TEM, ethanol-TPD, and H2-TPR. The perovskite-type oxides exhibit moderate activities in the ATRE reaction. Well dispersed Ni particles on lanthanum oxide species were obtained by reducing the LaNiO3 sample. It favors the dehydrogenation, decomposition of ethanol/acetaldehyde, methane reforming and water gas shift reactions, thus leads to good activity and H2 selectivity in ATRE reaction. Typically, 3.2 H2 molecules per ethanol molecule were produced at EtOH:H2O:O2 = 1:2:0.98 and GHSV = 4 × 105 h−1. A comparison between LaNiO3 derived and impregnated Ni/La2O3 shows that the LaNiO3 derived sample favored the dispersion of Ni, which increased the activity and the resistance to coke deposition.
Co-reporter:Jie Yan, Xin Li, Siyuan Yang, Xiujie Wang, Wuyi Zhou, Yueping Fang, Shanqing Zhang, Feng Peng, Shengsen Zhang
International Journal of Hydrogen Energy (12 January 2017) Volume 42(Issue 2) pp:
Publication Date(Web):12 January 2017
DOI:10.1016/j.ijhydene.2016.08.188
•CdS-sensitized hydrogenated branched TiO2 nanorod arrays composite is developed.•The Pt-wired photocatalysis system addresses the rate-limiting step of H2 production.•Pt acts as an electron super highway and effective catalytic site for H+ reduction.•The Pt-wired photocatalysis system exhibits exceptional H2 production efficiency.In recent years, tremendous efforts have been devoted to develop new photocatalyst with wide spectrum response for H2 generation from water or aqueous solution. In this work, CdS nanoparticles (NPs) have been immobilized on hydrogenated three-dimensional (3D) branched TiO2 nanorod arrays, resulting in a highly efficient photocatalyst, i.e, CdS/H-3D-TiO2. In addition, electrochemical reduction of H+ ion is identified as a limiting step in the photocatalytic generation of H2 at this catalyst, while here a Pt wired photocatalysis system (CdS/H-3D-TiO2/Pt-wire) is designed to overcome this barrier. Without the application of potential bias, visible light photocatalytic hydrogen production rate of CdS/H-3D-TiO2/Pt-wire is 18.42 μmol cm−2 h−1, which is 11.2 times that of CdS/H-3D-TiO2 without Pt (1.64 μmol cm−2 h−1). The Pt wire acts as an electron super highway between the FTO substrate and H+ ions to evacuate the generated electrons to H+ ions and catalyze the reduction reaction and consequently generate H2 gas. This work successfully offers a novel direction for dramatic improvement in H2 generation efficiency in photocatalysis field.CdS nanoparticles have been immobilized on hydrogenated three-dimensional (3D) branched TiO2 nanorod arrays, resulting in a highly efficient photocatalyst. A Pt-wired photocatalysis system is designed to substantially improve the photocatalytic performance.
Co-reporter:Xiaobo Fu, Hao Yu, Feng Peng, Hongjuan Wang, Yu Qian
Applied Catalysis A: General (11 April 2007) Volume 321(Issue 2) pp:
Publication Date(Web):11 April 2007
DOI:10.1016/j.apcata.2007.02.002
Ruthenium(IV) oxide (RuO2) nanoparticles supported by herringbone carbon nanotubes (CNTs) were synthesized by a homogenous-oxidation-precipitation (HOP) method with H2O2. The morphology and composition of the resulting composite were characterized by TEM, XPS, XRD, TG and TPR. CNTs exhibited the better ability to induce the formation of highly dispersed nanoparticles, compared with common used supports, such as γ-Al2O3 and activated carbon. Amorphous hydrous RuO2 nanoparticles uniformly dispersed on the surface of CNTs. The average size of RuO2 was significantly reduced to 1.35 nm. This result leads to the high activity and excellent selectivity, which has been demonstrated in the aerobic oxidation of alcohols to aldehydes or ketones. The new preparation technique of CNT-supported oxide nanoparticles reported in this paper has great potential for various catalytic applications.CNT-supported highly dispersed hydrous RuO2 nanoparticles can be facilely prepared by a homogenous oxidation precipitation method using hydrogen peroxide as both oxidant and precipitant at room temperature. This new method provides an effective way to prepare new catalysts for aerobic oxidation of alcohols and demonstrates the great potential of CNTs as catalyst supports.
Co-reporter:Xing Wan, Hongjuan Wang, Hao Yu, Feng Peng
Journal of Power Sources (1 April 2017) Volume 346() pp:80-88
Publication Date(Web):1 April 2017
DOI:10.1016/j.jpowsour.2017.02.030
Co-reporter:Yuhang Li, Guoyu Zhong, Hao Yu, Hongjuan Wang and Feng Peng
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 34) pp:NaN21959-21959
Publication Date(Web):2015/07/27
DOI:10.1039/C5CP02167G
It is highly challenging but extremely desirable to develop carbon catalysts with high oxygen reduction reaction (ORR) activity and stability in acidic medium for commercial application. In this paper, based on density functional theory (DFT) calculations with long range interaction correction and solvation effects, the elementary transformations of all the probable intermediates in the ORR and the hydrogen peroxide reduction reaction (HPRR) over graphitic nitrogen-doped carbon nanotubes (NCNTs) in acidic medium were evaluated, and it was found that all the rate determining steps are related to the bonding hydroxyl group because of the strong interaction between the hydroxyl group and carbon. Thus, it is hard for the direct four-electron ORR and the two-electron HPRR to proceed. Together with hydrogen peroxide disproportionation (HPD), a mixed mechanism for the ORR in acidic electrolyte was proposed, where the two-electron and three-electron ORRs and HPD dominate the electrode reaction. The experimental result for the ORR catalyzed by NCNTs in acidic electrolyte also well illustrated the rationality of the theoretical calculations. This study not only gives new insights into the effect of graphitic nitrogen doping on the ORR catalyzed by carbon, but also provides a guide to design carbon catalysts with high ORR activity in acidic electrolyte.
Co-reporter:Zhiwei Yao, Xiaohong Zhang, Feng Peng, Hao Yu, Hongjuan Wang and Jian Yang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 19) pp:NaN6902-6902
Publication Date(Web):2011/03/31
DOI:10.1039/C1JM10833F
MoN
nanoparticles in a size range around 50 nm were obtained on CNTs support via a novel carbothermal reduction nitridation (CRN). For the first time, a common (NH4)6Mo7O24·4H2O can be used as a Mo source to prepare MoN nanoparticles. A Mo-containing precursor was in a first step carburized and was reduced to a MoOxCy/Mo mixture. During further carbothermal nitridation this mixture-phase was shifted to the MoN phase through either a Mo2C or MoOxNy intermediate. Compared with the conventional NH3-temperature-programmed treatment (TPT) route that produced Mo nitride from MoO2 with rigorous heating method, the CRN route favored the formation of Mo nitride from easily nitridable MoOxCy/Mo, MoOxNy and Mo2C intermediates. The phase structure of the Mo nitride product was greatly dependent on nitridation reaction pathway. The NH3-TPT route yielded cubic Mo2N, while the CRN process produced hexagonal MoN.
Co-reporter:Yingsi Wu, Qianqian Shi, Yuhang Li, Zhuangchai Lai, Hao Yu, Hongjuan Wang and Feng Peng
Journal of Materials Chemistry A 2015 - vol. 3(Issue 3) pp:NaN1151-1151
Publication Date(Web):2014/11/18
DOI:10.1039/C4TA03850A
A new catalyst, cobalt carbonitride (CoCN) nanoparticles supported on nitrogen-doped graphenes (NG), was synthesized via a high temperature ammonia nitridation method. The catalyst has a core–shell structure with a highly active CoCN core and a protective cobalt oxide shell. Linear sweep voltammetry measurements show that the catalyst presents excellent activity in an oxygen reduction reaction compared to cobalt oxide supported on NG and commercial Pt/C catalysts, benefiting from the strong synergistic effect between CoCN and NG and the electronic modification of cobalt oxide by CoCN from within.
Co-reporter:Chunlin Chen, Jian Zhang, Bingsen Zhang, Changlin Yu, Feng Peng and Dangsheng Su
Chemical Communications 2013 - vol. 49(Issue 74) pp:NaN8153-8153
Publication Date(Web):2013/05/22
DOI:10.1039/C3CC41500G
Bulk nitrogen doping can efficiently improve the catalytic performance of carbon nanotubes (CNT) in oxidative dehydrogenation of propane (ODH). The graphitic nitrogen plays a determining role in enhancing their activity by speeding up the activation of oxygen and decreasing the overall activation energy of the reaction.
Co-reporter:Xiaosong Zhou, Bei Jin, Liandi Li, Feng Peng, Hongjuan Wang, Hao Yu and Yueping Fang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 34) pp:NaN17905-17905
Publication Date(Web):2012/07/13
DOI:10.1039/C2JM32686H
A carbon nitride/TiO2 nanotube array (CN/TNT) heterojunction photocatalyst with visible-light response was prepared by a simple electrochemical method. The photocatalyst was characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The photoelectrochemical properties and photocatalytic activities of the obtained-samples were systematically tested under visible light irradiation. The activity of heterojunction photocatalyst CN/TNTs is higher than that of TNTs. The obviously increased performance of CN/TNTs is ascribed mainly to enhancement of electron–hole separations both at the interface and in the semiconductors.
Co-reporter:Zhuangchai Lai, Feng Peng, Hongjuan Wang, Hao Yu, Shanqing Zhang and Huijun Zhao
Journal of Materials Chemistry A 2013 - vol. 1(Issue 13) pp:NaN4185-4185
Publication Date(Web):2013/02/12
DOI:10.1039/C3TA00188A
A facile and controllable hydrothermal approach is developed to synthesize rutile TiO2 single crystals with regulable (110), (111) and (001) facets without toxic capping agents. The normalized surface photoreactivity of the as-prepared TiO2 with (111) and (001) facets is approximately 5 times that of rutile TiO2 with majority (110) facets.
Co-reporter:Xiaosong Zhou, Feng Peng, Hongjuan Wang, Hao Yu and Yueping Fang
Chemical Communications 2011 - vol. 47(Issue 37) pp:NaN10325-10325
Publication Date(Web):2011/08/19
DOI:10.1039/C1CC13862F
Novel carbon nitride polymer sensitized TiO2 nanotube arrays with high photocatalytic activity and photoelectrochemical response under visible light irradiation are prepared by electrodeposition.
Co-reporter:Xiaosong Zhou, Feng Peng, Hongjuan Wang, Hao Yu and Yueping Fang
Chemical Communications 2012 - vol. 48(Issue 4) pp:NaN602-602
Publication Date(Web):2011/11/24
DOI:10.1039/C1CC15751E
Nanoscaled nitrogen doped anatase TiO2 with dominant (001) facets, which exhibited high photocatalytic activity and excellent photoelectrochemical properties under visible light irradiation, was successfully synthesized by solvothermal treatment of TiN in acidic NaBF4 solution for the first time.
Co-reporter:Yonghai Cao, Yuhang Li, Hao Yu, Feng Peng and Hongjuan Wang
Catalysis Science & Technology (2011-Present) 2015 - vol. 5(Issue 8) pp:NaN3944-3944
Publication Date(Web):2015/03/17
DOI:10.1039/C5CY00136F
Carbon nanotubes (CNTs) and nitrogen-doped CNTs (NCNTs) as metal-free catalysts exhibited an excellent activity in the selective oxidation of α-pinene with molecular oxygen as the terminal oxidant. Two distinct pathways, i.e. epoxidation and allylic oxidation, were active in this reaction. Enhancement of epoxidation was observed over CNTs, yielding the highest epoxidation/allylic oxidation products ratio. Excellent activity was achieved over NCNTs, giving 54.5% α-pinene conversion and 272.4 mmol g−1 h−1 mass-normalized activity, which compete with that of the state-of-the-art metal catalysts. Allylic oxidation was enhanced over NCNTs, using which equimolar amounts of epoxide and allylic products were produced. Thus, N-doping boosted the overall conversion and the yields of both epoxidation and allylic oxidation products, which was supported by the results of theoretical simulation.
Co-reporter:Hao Yu, Xiaobo Fu, Chunmei Zhou, Feng Peng, Hongjuan Wang and Jian Yang
Chemical Communications 2009(Issue 17) pp:NaN2410-2410
Publication Date(Web):2009/03/14
DOI:10.1039/B820063G
The activity of RuO2·xH2O/CNT for benzyl alcoholoxidation can be predicted by the specific capacitance (SC) of RuO2, suggesting that highly active RuO2 nanocatalysts are also good supercapacitor materials with SC high up to 1500 F gRuO2−1.
Co-reporter:Qianqian Shi, Feng Peng, Shixia Liao, Hongjuan Wang, Hao Yu, Ziwu Liu, Bingsen Zhang and Dangsheng Su
Journal of Materials Chemistry A 2013 - vol. 1(Issue 47) pp:NaN14857-14857
Publication Date(Web):2013/10/04
DOI:10.1039/C3TA12647A
Carbon materials have received an increasing amount of attention due to their low cost, long-term stability, and high electrocatalytic activity in catalyzing the cathodic oxygen reduction reaction (ORR). However, most of the carbon catalysts have exhibited their excellent activity only in alkaline media, which greatly hinders their practical application in polymer electrolyte membrane fuel cells (PEMFCs). In order to break the restriction of alkaline conditions, sulfur and nitrogen doped carbon nanotubes (SN-CNTs) were designed and successfully prepared via annealing of a mixture composed of nitrogen doped carbon nanotubes (N-CNTs) and sulfur. The result showed the as-prepared SN-CNTs have an enhanced ORR activity in both acidic and alkaline media compared with N doped CNTs (N-CNTs). This report also provides a new approach to explore low-cost electrocatalysts for practical fuel cell applications.
Co-reporter:Zhuangchai Lai, Feng Peng, Yun Wang, Hongjuan Wang, Hao Yu, Porun Liu and Huijun Zhao
Journal of Materials Chemistry A 2012 - vol. 22(Issue 45) pp:NaN23912-23912
Publication Date(Web):2012/09/25
DOI:10.1039/C2JM34880B
A facile hydrothermal approach for synthesizing anatase TiO2 single crystals with wholly {100} and {001} facets under a reaction temperature as low as 100 °C is reported. NaBF4 and NaF are used as the facet control agents instead of HF, which are safer and much easier to use. By adjusting the reaction conditions, the lowest energy {101} facets can be completely eliminated. The anatase TiO2 with 45% {100} and 55% {001} facets exhibits a considerably higher specific surface photoreactivity than P25. The formation mechanism of the high surface energy facets is explored by XPS and DFT calculations. The results confirm that the reactions of the –OH groups on the surface of anatase TiO2 that are replaced by F atoms are exothermic and can lower the surface energy of {100} and {001} facets, indicating that anatase TiO2 with pure high energy facets can be prepared at temperatures as low as 100 °C with the existence of the surface lattice F. It is the first report that the surface lattice F generated in the reaction may stabilize and lead to the disappearance of the lowest surface energy {101} facet under low temperature.
Co-reporter:Yumei Chi, Mingli Zhu, Yuhang Li, Hao Yu, Hongjuan Wang and Feng Peng
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 7) pp:NaN2402-2402
Publication Date(Web):2015/11/19
DOI:10.1039/C5CY01631B
It is of particular interest to reveal the influence of surface oxygenated groups and surface defects of carbon catalysts on liquid phase oxidation reactions. Herein, surface oxygenated groups and defects were introduced on the surface of carbon nanotubes (CNTs) using a gas-phase oxidation method with O2 and a liquid-phase oxidation method with concentrated HNO3. The results strongly confirm that the surface oxygenated groups on CNTs have a negative effect on catalytic activity for cumene oxidation. To the best of our knowledge, for the first time, we have distinguished experimentally that the factor responsible for the decrease in catalytic activity of the oxidized CNTs for the liquid phase aerobic oxidation reaction is the surface oxygenated groups instead of the surface defects. Meanwhile, the mechanism that drives the decrease in catalytic activity of the oxidized CNTs has also been revealed. It has been proven that the oxidized CNTs serve as free radical quenchers, capturing the free radical intermediates of the reaction and inhibiting the free radical chain transfer, thereby reducing the catalytic activity of the free radical reaction in the liquid phase. This study gains a new insight into the effect of surface structures on carbon-catalyzed liquid phase oxidation, and further pushes forward the research on carbon catalysis.
Co-reporter:Yonghai Cao, Xianyu Luo, Hao Yu, Feng Peng, Hongjuan Wang and Guoqing Ning
Catalysis Science & Technology (2011-Present) 2013 - vol. 3(Issue 10) pp:NaN2660-2660
Publication Date(Web):2013/06/28
DOI:10.1039/C3CY00256J
The catalytic properties of sp2- and sp3-hybridized carbons, represented by graphene and diamond, in the selective oxidation of cyclohexane were investigated to understand the structure dependence of carbon materials in the reaction. sp2 carbons showed the higher activity than sp3 carbons. The highest activity was obtained over mesoporous graphene, a representative sp2-hybridized carbon, yielding a weight-normalized activity of 162.6 mmol g−1 h−1. The excellent performance of sp2 carbons was rationalized by their ability to catalyze the decomposition of peroxide intermediates, such as cyclohexyl hydroperoxide, which promoted the oxidative reaction to produce cyclohexanol and cyclohexanone.
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