Co-reporter:Yahui Sun, Jianghong Zhao, Jianlong Wang, Nan Tang, Rijie Zhao, Dongdong Zhang, Taotao Guan, and Kaixi Li
The Journal of Physical Chemistry C May 11, 2017 Volume 121(Issue 18) pp:10000-10000
Publication Date(Web):April 25, 2017
DOI:10.1021/acs.jpcc.7b02195
Millimeter-sized activated carbon spheres are potential candidates for industrial-scale CO2 capture. Millimeter-sized sulfur-doped microporous activated carbon spheres were synthesized from poly(styrene–divinylbenzene), a very cheap and easily operated resin product, in the present work and studied for CO2 uptake. A series of sulfur-doped spherical carbon materials were yielded through the sulfonation, oxidation, carbonization, and KOH activation of the polymer precursors. In addition to promoting the cross-linking of the polymer molecules, the sulfonic substituents directly introduced sulfur functional groups into the carbon materials after pyrolysis. The SCS-700 sample showed the best CO2 adsorption performance, whose sulfur content reached 0.69 wt %, and exhibited a high surface area of 1526 m2 g–1 and a large pore volume of 0.726 cm3 g–1. The adsorbent showed high CO2 uptake at both 25 °C (4.21 mmol g–1) and 50 °C (2.54 mmol g–1) under ambient pressure due to its abundant ultramicropores and a high proportion of oxidized sulfur functional groups. Thanks to its high microporous volume of 0.617 cm3 g–1, the CO2 performance at 8 bar was 10.66 mmol g–1 at 25 °C. The thermodynamics indicated the exothermic and spontaneous nature of the adsorption process, which was dominated by a physisorption mechanism. Furthermore, the CO2 uptake curves on a TGA analyzer were fitted with different kinetic models, and the fractional order model showed the best agreement with the experimental data. The recycling curve of SCS-700 exhibited excellent cyclic adsorption performance with no significant capacity loss even after ten adsorption–desorption cycles. It is suggested that this excellent CO2 uptake was due to the synergistic effect of the well-developed microporous structure and the oxidized sulfur-containing functional groups.
Co-reporter:Pengju Yang, Jianghong Zhao, Wei Qiao, Li Li and Zhenping Zhu
Nanoscale 2015 vol. 7(Issue 45) pp:18887-18890
Publication Date(Web):20 Oct 2015
DOI:10.1039/C5NR05570A
We report a new and effective method to prepare high activity graphitic carbon nitride (g-C3N4) by a simple ammonia etching treatment. The obtained g-C3N4 displays a high BET surface area and enhanced electron/hole separation efficiency. The hydrogen evolution rates improved from 52 μmol h−1 to 316.7 μmol h−1 under visible light.
Co-reporter:Pengju Yang, Jianghong Zhao, Jian Wang, Baoyue Cao, Li Li and Zhenping Zhu
Journal of Materials Chemistry A 2015 vol. 3(Issue 1) pp:136-138
Publication Date(Web):13 Nov 2014
DOI:10.1039/C4TA05155F
We report a new method to prepare photoluminescent carbon nanoparticles (CNPs) by a light-induced process. The obtained CNPs are sensitive to the specific detection of Fe3+ with a detection limit of 0.55 ppm. CNPs also show excellent photocatalytic hydrogen production under xenon lamp irradiation. The hydrogen evolution rate is up to 4.89 μmol h−1 over 2.1 mg CNPs.
Co-reporter:Pengju Yang, Jianghong Zhao, Jian Wang, Baoyue Cao, Li Li and Zhenping Zhu
Journal of Materials Chemistry A 2015 vol. 3(Issue 16) pp:8256-8259
Publication Date(Web):16 Mar 2015
DOI:10.1039/C5TA00657K
Carbon nanodots without any modification can drive photocatalytic hydrogen evolution. More importantly, we found that Z-scheme is an effective strategy to improve the photocatalytic performance of carbon nanodots. The photocatalytic H2-evolution rates improve from 4.65 μmol g−1 h−1 to 1330 μmol g−1 h−1 under xenon lamp irradiation.
Co-reporter:Pengju Yang, Jianghong Zhao, Jian Wang, Huijuan Cui, Li Li and Zhenping Zhu
RSC Advances 2015 vol. 5(Issue 27) pp:21332-21335
Publication Date(Web):17 Feb 2015
DOI:10.1039/C5RA01924A
Pure carbon nanodots (CNDs) without any modification and co-catalyst can drive photocatalytic hydrogen generation. The hydrogen generation rate of CNDs reaches 3615.3 μmol g−1 h−1 when methanol was used as the sacrificial donor, which is 34.8 times higher than that of commercial Degussa P25 photocatalyst under the same conditions. Moreover, the CNDs show good stability; the hydrogen generation rate has negligible change even after four cycles of testing.
Co-reporter:Dr. Pengju Yang;Dr. Jianghong Zhao;Dr. Lexi Zhang;Li Li;Dr. Zhenping Zhu
Chemistry - A European Journal 2015 Volume 21( Issue 23) pp:8561-8568
Publication Date(Web):
DOI:10.1002/chem.201405088
Abstract
Understanding the photoluminescence (PL) and photocatalytic properties of carbon nanodots (CNDs) induced by environmental factors such as pH through surface groups is significantly important to rationally tune the emission and photodriven catalysis of CNDs. Through adjusting the pH of an aqueous solution of CNDs, it was found that the PL of CNDs prepared by ultrasonic treatment of glucose is strongly quenched at pH 1 because of the formation of intramolecular hydrogen bonds among the oxygen-containing surface groups. The position of the strongest PL peak and its corresponding excitation wavelength strongly depend on the surface groups. The origins of the blue and green emissions of CNDs are closely related to the carboxyl and hydroxyl groups, respectively. The deprotonated COO− and CO− groups weaken the PL peak of the CNDs and shift it to the red. CNDs alone exhibit photocatalytic activity towards degradation of Rhodamine B at different pH values under UV irradiation. The photocatalytic activity of the CNDs is the highest at pH 1 because of the strong intramolecular hydrogen bonds formed among the oxygen-containing groups.
Co-reporter:Dr. Pengju Yang;Dr. Jianghong Zhao;Dr. Baoyue Cao;Li Li;Dr. Zhijian Wang;Dr. Xuxia Tian;Dr. Suping Jia;Dr. Zhenping Zhu
ChemCatChem 2015 Volume 7( Issue 15) pp:2384-2390
Publication Date(Web):
DOI:10.1002/cctc.201500326
Abstract
2,3-Butanediol (2,3-BD) was synthesized through TiO2-photocatalytic CC coupling of bioethanol synchronously with the liberation of an energy H2 molecule in an anaerobic atmosphere. It was found that the selectivity of 2,3-BD is controlled by the amount of .OH. The less the .OH, the higher the 2,3-BD selectivity. Furthermore, it was revealed that the amount of .OH increases with the increasing of the surface OH groups on TiO2 photocatalyst. The introduction of water is in favor of the CC coupling pathway. This can be attributed to the stronger interaction between water and TiO2, which is beneficial to recovering the OH groups and promoting the desorption of .CH(OH)CH3 intermediates, thus suppressing the thermodynamically favorable overoxidation of .CH(OH)CH3 into acetaldehyde and promoting the CC coupling into 2,3-BD. Based on the findings, the 2,3-BD selectivity was greatly enhanced from approximately 2.6 % to approximately 65 % over Degussa P25-TiO2 photocatalyst through fluorine substitution of surface OH groups.
Co-reporter:Jin-ling Song, Jiang-hong Zhao, Jian-feng Zheng, Zhen-ping Zhu
New Carbon Materials 2013 Volume 28(Issue 3) pp:191-198
Publication Date(Web):June 2013
DOI:10.1016/S1872-5805(13)60076-1
Co-reporter:Jian Wang, Bo Li, Jiazang Chen, Na Li, Jianfeng Zheng, Jianghong Zhao, Zhenping Zhu
Applied Surface Science 2012 Volume 259() pp:118-123
Publication Date(Web):15 October 2012
DOI:10.1016/j.apsusc.2012.07.003
Abstract
To investigate the role of metal sulfides as co-catalyst for photocatalytic hydrogen production under visible light irradiation, we have loaded small amounts of transition-metal sulfides (MS), such as NiS, CoS and CuS, onto the surface of CdxZn1−xS solid solution. It can be found that the rate of H2 evolution over the MS/Cd0.4Zn0.6S was 5 times higher than that of the pure Cd0.4Zn0.6S, and is comparable to the Cd0.4Zn0.6S modified with 1 wt% platinum (Pt) co-catalysts. The MS/Cd0.4Zn0.6S photocatalysts were characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV–visible spectrophotometer (UV–vis), and photoluminescence (PL) spectroscopy. It can be speculated that the MS provided active sites for H2 production and caused the migration of excited electrons from Cd0.4Zn0.6S toward MS, leading to the enhancement of photocatalytic activity.
Co-reporter:Lexi Zhang, Jianghong Zhao, Haiqiang Lu, Li Li, Jianfeng Zheng, Hui Li, Zhenping Zhu
Sensors and Actuators B: Chemical 2012 Volume 161(Issue 1) pp:209-215
Publication Date(Web):3 January 2012
DOI:10.1016/j.snb.2011.10.021
Zinc oxide (ZnO) nanosheets were successfully synthesized through a facile, economic, and low-temperature hydrothermal process, followed by annealing of the zinc carbonate hydroxide hydrate precursors. The nanosheets are single crystals with hexagonal wurtzite and mesoporous structures. Gas sensors based on these ZnO nanosheets exhibited ultrahigh response, fast response–recovery, and good selectivity and stability to 0.01–1000 ppm (parts per million) ethanol at 400 °C. Extremely low concentration ethanol (down to 10 ppb (parts per billion)) can be readily detected (S = 3.05 ± 0.21), which is the lowest detection limit to ethanol utilizing pure ZnO as sensing materials in a one-side heated gas sensor hitherto. The excellent ethanol-sensing performance of ZnO, particularly the ppb-level response, is mainly attributed to its novel hierarchical structure, which has a large specific surface area, abundant mesopores, single-crystal structure, plane-contact between sheets, three-dimensional network architecture, and characteristically small thickness.
Co-reporter:Lexi Zhang, Jianghong Zhao, Jianfeng Zheng, Li Li, Zhenping Zhu
Applied Surface Science 2011 Volume 258(Issue 2) pp:711-718
Publication Date(Web):1 November 2011
DOI:10.1016/j.apsusc.2011.07.116
Abstract
Shuttle-like ZnO nano/microrods were successfully synthesized via a low temperature (80 °C), “green” (without any organic solvent or surfactant) and simple hydrothermal process in the solution of zinc chloride and ammonia water. X-ray diffraction and Raman spectroscopy indicated that the ZnO nano/microrods are a well-crystallized hexagonal wurtzite structure. Yet photoluminescence analysis showed that abundant intrinsic defects (52.97% electron donor defects and 45.49% electron acceptor defects) exist on the surface of ZnO crystals. Gas sensors based on the shuttle-like ZnO nano/microrods exhibited high sensitivity, rapid response–recovery and good selectivity to formaldehyde in the range of 10–1000 ppm at an optimum operating temperature of 400 °C. Through applying linear fitting to the plot of sensitivity versus formaldehyde concentration in logarithmic forms, the chemisorbed oxygen species on the ZnO surface were found to be O2− (highly active among O2, O2− and O− species). Notably, formaldehyde can be easily distinguished from acetaldehyde with a selectivity of about 3. The high formaldehyde sensitivity is mainly attributed to the synergistic effect of abundant electron donor defects (52.97%) and highly active oxidants (surface adsorbed O2− species) co-existed on the surfaces of ZnO.
Co-reporter:Haiqiang Lu, Jianghong Zhao, Li Li, Jianfeng Zheng, Lexi Zhang, Liming Gong, Zhijian Wang, Zhenping Zhu
Chemical Physics Letters 2011 Volume 508(4–6) pp:258-264
Publication Date(Web):27 May 2011
DOI:10.1016/j.cplett.2011.04.044
A systematic study on hydrothermal treatment of titania recording the changes of morphologies of titanate nanostructures was performed by subtly controlled termination of reaction and capture of intermediates. During the hydrothermal process, rapid coalescence of nanoparticles first occurred, followed by exfoliation of large aggregated moieties in their peripheries into nanosheets. The nanosheets were then rolled up to form short nanotubes. Afterwards, the nanotubes transformed into long ones, which eventually assembled into nanowires. This is a stepwise evolution process common for alkaline hydrothermal transitions. The oriented attachment (OA) model plays a vital role here, and the Oswald ripening (OR) mechanism appears to be effective as well.Graphical abstractHighlights► Oriented attachment (OA) runs through the whole hydrothermal process. ► Smaller nanoparticles aggregate into larger particles mainly by the OA mechanism. ► Lamellar nanosheets through peeling off from the large powders. ► Short titanate nanotubes transform to longer nanotubes through OA process.
Co-reporter:Guixiang Ma ; Rongrong Jia ; Jianghong Zhao ; Zhijian Wang ; Chang Song ; Suping Jia ;Zhenping Zhu
The Journal of Physical Chemistry C 2011 Volume 115(Issue 50) pp:25148-25154
Publication Date(Web):November 8, 2011
DOI:10.1021/jp208257r
To propel the commercialization of fuel cells, the development of efficient nonprecious metal catalysts, specifically cathodic oxygen reduction catalysts, is turning into reality because the great advancements have been made on nitrogen-doped carbon materials recently. In this study, we demonstrated that nitrogen-doped hollow carbon nanoparticles (N-HCNPs) exhibit excellent electrocatalytic performance for oxygen reduction reaction (ORR) in alkaline fuel cells. Cyclic voltammetry and rotating ring-disk electrode voltammetry showed that the ORR activity of N-HCNPs approaches that of commercial Pt–C catalyst and is much better compared with nitrogen-free counterparts due to the incorporation of nitrogen atoms into graphitic structures. Kinetic studies indicated that the involvement of nitrogen induces a totally different oxygen adsorption mechanism and a four-electron dominated reaction pathway for N-HCNPs in comparison with nitrogen-free HCNPs, very similar to the observations in Pt–C. Moreover, N-HCNPs exhibited good operation stability and excellent tolerance to methanol crossover and CO poisoning for ORR superior to that of Pt–C. Our findings suggest that N-HCNPs catalyst is a promising alternative for the Pt-based catalysts in fuel cells.
Co-reporter:Lexi Zhang, Jianghong Zhao, Jianfeng Zheng, Li Li, Zhenping Zhu
Sensors and Actuators B: Chemical 2011 Volume 158(Issue 1) pp:144-150
Publication Date(Web):15 November 2011
DOI:10.1016/j.snb.2011.05.057
Nanoparticle-decorated ZnO microdisks showing a hierarchical structure were successfully synthesized through a citric acid-assisted hydrothermal process. The ZnO microdisks had a hexagonal wurtzite structure with high crystallinity. Sensors based on these microdisks exhibited high response values, fast response–recovery, good selectivity and long-term stability to 1–4000 ppm acetylene at 420 °C. In addition, even 1 ppm acetylene can be detected with high response (S = 7.9). The hierarchical structure can facilitate to fix the ZnO nanoparticles leading to a less aggregated configuration, which is expected to contribute much to the excellent acetylene sensing properties at high temperatures.Highlights► Hierarchical ZnO microdisks were synthesized to restrain nanoparticle aggregation. ► The microdisk sensors exhibited excellent acetylene sensing properties. ► The high response profits from the well-dispersed ZnO nanoparticles and the active O2− species.
Co-reporter:Lexi Zhang, Jianghong Zhao, Haiqiang Lu, Liming Gong, Li Li, Jianfeng Zheng, Hui Li, Zhenping Zhu
Sensors and Actuators B: Chemical 2011 160(1) pp: 364-370
Publication Date(Web):
DOI:10.1016/j.snb.2011.07.062
Co-reporter:Rongrong Jia, Jiazang Chen, Jianghong Zhao, Jianfeng Zheng, Chang Song, Li Li and Zhenping Zhu
Journal of Materials Chemistry A 2010 vol. 20(Issue 48) pp:10829-10834
Publication Date(Web):09 Oct 2010
DOI:10.1039/C0JM01799J
Hollow carbon nanoparticles that have been highly doped with nitrogen (N-HCNPs) are directly prepared by a facile one-pot method based on the detonation-assisted chemical vapor deposition of dimethylformamide without the use of metal catalysts. The N-HCNPs exhibit uniform core-shell microstructures with inner cavities encapsulated by graphitic walls, possessing a narrow size distribution of 10–25 nm. The nitrogen content in N-HCNPs is as high as 20.8% atom ratio, and the nitrogen bonds display pyridine-, pyrrole-, and graphite-like configurations. Defects and dislocations are present in the graphene layers due to highly incorporated nitrogen, leading to the creation of micropores on the carbon shell and a large BET surface area of 454 m2 g−1. The unique N-HCNPs with interconnected hierarchical porous structures and nitrogen-containing defects show excellent electrocatalytic activity for triiodide reduction in dye-sensitized solar cells, superior to conventional platinum catalysts.
Co-reporter:Shuli Bai, Jianghong Zhao, Zhenping Zhu
Applied Surface Science 2010 Volume 256(Issue 6) pp:1689-1693
Publication Date(Web):1 January 2010
DOI:10.1016/j.apsusc.2009.09.095
Abstract
Tube-in-tube carbon nanostructures (TTCNTs) have been successfully constructed on liquid membranes via a hydrogen-bonding linkage of small graphene sheets around normal carbon nanotubes (CNTs). The effects of solvent (water, tetrahydrofuran (THF), ethanol, n-hexane and N,N-dimethylformamide (DMF)) and membrane thickness on the assembling process were investigated. Results show that the formed cavity of TTCNTs becomes large with the increase of viscosity of solvent and pressure. The formed liquid membrane on CNTs surface plays a key role in this process, and it can be controlled by adjusting the membrane thickness and solvent nature. Moreover, TTCNTs show excellent catalytic reduction NO ability at low temperatures.
Co-reporter:Shouai Feng, Jianghong Zhao, Zhenping Zhu
Materials Science and Engineering: B 2008 Volume 150(Issue 2) pp:116-120
Publication Date(Web):15 May 2008
DOI:10.1016/j.mseb.2008.02.002
A common problem in the fabrication of nanostructures is their undesired aggregation due to their high surface free energy. Here we show that a combinatorial control of reaction kinetic parameters such as feeding rate of reactant and reaction temperature can effectively restrain the aggregation of ZnS nanocrystals. The restraining process is associated with a stabilization of ZnS nanocrystal surfaces. Slowing down the feeding rate of reactants allows formed ZnS nanocrystals to get enough time to stabilize their surfaces. The stabilization of ZnS nanocrystal surfaces is further improved by suitably increasing reaction temperature. As a result, well dispersed and uniform ZnS nanocrystals with diameter of 4–6 nm are obtained with a common reaction between Zn(NO3)2 and Na2S, which is normally viewed to easily cause an aggregation. The results of photocatalytic degradation of methylene blue show that the aggregation restraint can effectively improve the activity of ZnS nanocrystals.
Co-reporter:Liming Gong, Jian Wang, Hui Li, Li Wang, Jianghong Zhao, Zhenping Zhu
Catalysis Communications (1 July 2011) Volume 12(Issue 12) pp:1099-1103
Publication Date(Web):1 July 2011
DOI:10.1016/j.catcom.2011.03.024
Acriflavine dye, with a long-lived triplet excited state, has a strong sensitizing ability for photodriven water splitting when [CoIII(dmgH)2(py)Cl] complex is used as a catalyst and triethanolamine as electron donor. This catalytic system is an example of a noble-metal-free homogeneous system for hydrogen generation from water. Moreover, the mechanistic details of the overall reaction pathway, as well as Acriflavine fading, is presented to offer significant guidance to developing more robust photocatalytic systems.Download full-size imageResearch highlights►A noble-metal-free homogeneous photocatalytic system based on Acriflavine + cobaloxime + triethanolamine was constructed. ►110 turnovers of H2 per Acriflavine were obtained after 2 h irradiation ►The mechanistic details on both the reaction pathway and Acriflavine fading were revealed by UV–vis absorption spectra of photolysis solutions.
Co-reporter:Pengju Yang, Jianghong Zhao, Jian Wang, Baoyue Cao, Li Li and Zhenping Zhu
Journal of Materials Chemistry A 2015 - vol. 3(Issue 1) pp:NaN138-138
Publication Date(Web):2014/11/13
DOI:10.1039/C4TA05155F
We report a new method to prepare photoluminescent carbon nanoparticles (CNPs) by a light-induced process. The obtained CNPs are sensitive to the specific detection of Fe3+ with a detection limit of 0.55 ppm. CNPs also show excellent photocatalytic hydrogen production under xenon lamp irradiation. The hydrogen evolution rate is up to 4.89 μmol h−1 over 2.1 mg CNPs.
Co-reporter:Rongrong Jia, Jiazang Chen, Jianghong Zhao, Jianfeng Zheng, Chang Song, Li Li and Zhenping Zhu
Journal of Materials Chemistry A 2010 - vol. 20(Issue 48) pp:NaN10834-10834
Publication Date(Web):2010/10/09
DOI:10.1039/C0JM01799J
Hollow carbon nanoparticles that have been highly doped with nitrogen (N-HCNPs) are directly prepared by a facile one-pot method based on the detonation-assisted chemical vapor deposition of dimethylformamide without the use of metal catalysts. The N-HCNPs exhibit uniform core-shell microstructures with inner cavities encapsulated by graphitic walls, possessing a narrow size distribution of 10–25 nm. The nitrogen content in N-HCNPs is as high as 20.8% atom ratio, and the nitrogen bonds display pyridine-, pyrrole-, and graphite-like configurations. Defects and dislocations are present in the graphene layers due to highly incorporated nitrogen, leading to the creation of micropores on the carbon shell and a large BET surface area of 454 m2 g−1. The unique N-HCNPs with interconnected hierarchical porous structures and nitrogen-containing defects show excellent electrocatalytic activity for triiodide reduction in dye-sensitized solar cells, superior to conventional platinum catalysts.
Co-reporter:Pengju Yang, Jianghong Zhao, Jian Wang, Baoyue Cao, Li Li and Zhenping Zhu
Journal of Materials Chemistry A 2015 - vol. 3(Issue 16) pp:NaN8259-8259
Publication Date(Web):2015/03/16
DOI:10.1039/C5TA00657K
Carbon nanodots without any modification can drive photocatalytic hydrogen evolution. More importantly, we found that Z-scheme is an effective strategy to improve the photocatalytic performance of carbon nanodots. The photocatalytic H2-evolution rates improve from 4.65 μmol g−1 h−1 to 1330 μmol g−1 h−1 under xenon lamp irradiation.
