The photocatalytic decomposition of water to produce hydrogen is an important process,through which solar energy can be converted to chemical energy.Non-precious metal phosphides have quietly attracted attention as an...The photocatalytic decomposition of water to produce hydrogen is an important process,through which solar energy can be converted to chemical energy.Non-precious metal phosphides have quietly attracted attention as an emerging inexpensive photocatalyst.In this study,we reported that a CoP/CeVO4 hybrid photocatalyst exhibited high hydrogen evolution efficiency owing to EY(eosin Y)sensitization under visible light irradiation for the first time,and the amount of generated hydrogen reached 444.6μmol in 5 h.The CoP/CeVO4 nanohybrids were synthesized by a simple chemical precipitation method.The coupling of CoP and CeVO4 with ZIF-9 as a precursor could be completed in one step.The CeVO4 particles were firmly attached to the surface of the CoP particles to form a"small point"to"big point"heterojunction.The results of X-ray diffraction,X-ray photoelectron spectroscopy,scanning electron microscopy,EDX,and transmission electron microscopy showed the formation of CoP and CeVO4 nanoparticles and the structure of the composite.Based on a detailed analysis of the Mott-Schottky plot,the UV-vis diffuse reflectance spectra,photocurrent-time(it)curve,Tafel curve,Nyquist curve(EIS),linear volt-ampere curve(LSV),and steady-state fluorescence spectra were studied.The time-resolved photoluminescence measurements indicated that the reason for the high-efficiency hydrogen evolution of CoP/CeVO4 was that the bands of CoP and CeVO4 were bent due to the existence of the Schottky barrier,and a heterojunction was formed between CoP and CeVO4,which generated an internal electric field and accelerated the charge transfer.In addition,the synergistic effect between CoP and CeVO4 provided a new hydrogen-evolution activity center for each of them.The improved carrier separation efficiency and the decrease in the photo-generated recombination rate led to the excellent photocatalytic hydrogen-evolution activity of the CoP/CeVO4 composite catalyst.This work provides a new strategy for modulating the electronic structure and carrier behavior of transition metal phosphide photocatalysts.展开更多
CeVO4, CeMo0.01V0.99O4 and CeMo0.03V0.97O4 were prepared by co-precipitation method. The addition of molybdenum as promoter shows a positive effect on the catalytic behavior of CeVO4 in oxidative dehydrogenation of pr...CeVO4, CeMo0.01V0.99O4 and CeMo0.03V0.97O4 were prepared by co-precipitation method. The addition of molybdenum as promoter shows a positive effect on the catalytic behavior of CeVO4 in oxidative dehydrogenation of propane to propylene. The reduction behaviors of the catalysts were characterized by temperature-programmed reduction. The activation energies of reduction process for the catalysts were obtained at different reduction rates by Kissinger method. The addition of Mo to CeVO4 enhances the selectivity to propylene.展开更多
Shape controlled structure of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce（NO3）3·6H2O. The resulting products were characterized by X-ray powder diffr...Shape controlled structure of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce（NO3）3·6H2O. The resulting products were characterized by X-ray powder diffraction （XRD）, electron microscopy （SEM） and other techniques. On the basis of the experimental results, CeVO4 nanoparticles exhibited the crystal tetragonal structure and the pH value of solu-tion had an important effect on the crystal structure and morphology of CeVO4 nanoparticles. Furthermore, the tribological properties of CeVO4 nanoparticles as additives in liquid paraffin were evaluated on a four-ball tester. The results indicated that the wear resistance was im-proved by the additive CeVO4 nanoparticles which exhibited very good antiwear and friction reduction performance in wear.展开更多
The CeVO_4/graphitic C_3N_4 composites have exhibited much enhanced photocatalytic property for degrading methylene blue(MB) pollutant under visible light irradiation compared with single-phase g-C_3N_4 or CeVO_4. The...The CeVO_4/graphitic C_3N_4 composites have exhibited much enhanced photocatalytic property for degrading methylene blue(MB) pollutant under visible light irradiation compared with single-phase g-C_3N_4 or CeVO_4. The composite S5 obtained from an optimized mass ratio(5%) of CeVO_4 to dicyanamide(DCDA) exhibits the highest photocatalytic activity. Here, ternary Ag/CeVO_4/g-C_3N_4 composites denoted as X%Ag/S5 were prepared by an ultrasonic precipitation method to improve the photocatalytic property of S5. The TEM images show that CeVO_4 and Ag nanoparticles are well distributed on the layered g-C_3N_4, which agree well with the XRD results. The UV spectra show that the 7%Ag/S5 sample has the widest absorption range and the enhanced absorption intensity under visible light irradiation. The corresponding band gap of 7%Ag/S5(2.5 eV) is much lower than that of S5(2.65 eV). The corresponding k value of 7%Ag/S5 is much higher than those of g-C_3N_4 and CeVO_4. The degradation experiments for MB solution suggest that the 7%Ag/S5 sample has the optimal photocatalytic performance, which can degrade MB solution completely within 120 min. The enhanced photocatalytic property of the composites is ascribed to not only the effect of heterojunction structure, but also the surface plasma resonance effect of Ag nanoparticles.展开更多
Selective-controlled structure and shape of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce（NO3）3·6H2O.The resulting products were characterized by X-ray...Selective-controlled structure and shape of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce（NO3）3·6H2O.The resulting products were characterized by X-ray powder diffraction （XRD）,field emission scanning electron microscopy （FESEM） and energy dispersive spectroscopy （EDS）.The influence of hydrothermal temperature,precursor solution concentration on the crystal and morphology of products were further studied.The results showed that the as-synthesized products exhibited pure single-crystal CeVO4 nanoparticles with tetragonal structure.The hydrothermal temperature and precursor solution concentration had important effects on the formation of CeVO4 nanoparticles.Furthermore,the growth mechanism of CeVO4 nanoparticles was explained with Ostwald ripening mechanism.展开更多
Pure CeVO_(4) and Dy-doped CeVO_(4) nanorods containing different weight contents of Dy dopant were synthesized by hydrothermal method.Effect of Dy dopant on photodegradation of methylene blue(MB)and rhodamine B(RhB) ...Pure CeVO_(4) and Dy-doped CeVO_(4) nanorods containing different weight contents of Dy dopant were synthesized by hydrothermal method.Effect of Dy dopant on photodegradation of methylene blue(MB)and rhodamine B(RhB) was evaluated under UV light irradiation within 80 min.Pure CeVO_(4) and Dydoped CeVO_(4) nanorods were characterized by X-ray diffraction(XRD),Raman spectroscopy,transmission electron microscopy(TEM) and UV-visible spectroscopy.In this research,CeVO_(4) nanorods are tetragonal phase with the detection of main peak shift after being doped with Dy.The length of nanorods is deceased from 50 to 200 nm for pure CeVO_(4) to 50-100 nm for 3% Dy-doped CeVO_(4).Photodegradation of MB and RhB by CeVO_(4) nanorods under UV light irradiation is improved by Dy-dopant that plays the role in accepting electrons and reducing electron-hole recombination.MB and RhB solutions degraded by 3% Dy-doped CeVO_(4) nanorods was 94% and 93% within 80 min,respectively.展开更多
基金financially supported by the National Natural Science Foundation of China(21862002,41663012)the Graduate Innovation Project of the North Minzu University(YCX19113)the new technology and system for clean energy catalytic production,Major scientific project of North Minzu University(ZDZX201803)~~
文摘The photocatalytic decomposition of water to produce hydrogen is an important process,through which solar energy can be converted to chemical energy.Non-precious metal phosphides have quietly attracted attention as an emerging inexpensive photocatalyst.In this study,we reported that a CoP/CeVO4 hybrid photocatalyst exhibited high hydrogen evolution efficiency owing to EY(eosin Y)sensitization under visible light irradiation for the first time,and the amount of generated hydrogen reached 444.6μmol in 5 h.The CoP/CeVO4 nanohybrids were synthesized by a simple chemical precipitation method.The coupling of CoP and CeVO4 with ZIF-9 as a precursor could be completed in one step.The CeVO4 particles were firmly attached to the surface of the CoP particles to form a"small point"to"big point"heterojunction.The results of X-ray diffraction,X-ray photoelectron spectroscopy,scanning electron microscopy,EDX,and transmission electron microscopy showed the formation of CoP and CeVO4 nanoparticles and the structure of the composite.Based on a detailed analysis of the Mott-Schottky plot,the UV-vis diffuse reflectance spectra,photocurrent-time(it)curve,Tafel curve,Nyquist curve(EIS),linear volt-ampere curve(LSV),and steady-state fluorescence spectra were studied.The time-resolved photoluminescence measurements indicated that the reason for the high-efficiency hydrogen evolution of CoP/CeVO4 was that the bands of CoP and CeVO4 were bent due to the existence of the Schottky barrier,and a heterojunction was formed between CoP and CeVO4,which generated an internal electric field and accelerated the charge transfer.In addition,the synergistic effect between CoP and CeVO4 provided a new hydrogen-evolution activity center for each of them.The improved carrier separation efficiency and the decrease in the photo-generated recombination rate led to the excellent photocatalytic hydrogen-evolution activity of the CoP/CeVO4 composite catalyst.This work provides a new strategy for modulating the electronic structure and carrier behavior of transition metal phosphide photocatalysts.
基金supported by the National Natural Science Foundation of China (No. 21076056 and 20973096)the National Basic Research Program of China (No. 2009CB623502)the Program for Changjiang Scholars and Innovative Research Team in University (IRT0927)
文摘CeVO4, CeMo0.01V0.99O4 and CeMo0.03V0.97O4 were prepared by co-precipitation method. The addition of molybdenum as promoter shows a positive effect on the catalytic behavior of CeVO4 in oxidative dehydrogenation of propane to propylene. The reduction behaviors of the catalysts were characterized by temperature-programmed reduction. The activation energies of reduction process for the catalysts were obtained at different reduction rates by Kissinger method. The addition of Mo to CeVO4 enhances the selectivity to propylene.
基金supported by the State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences (0804)
文摘Shape controlled structure of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce（NO3）3·6H2O. The resulting products were characterized by X-ray powder diffraction （XRD）, electron microscopy （SEM） and other techniques. On the basis of the experimental results, CeVO4 nanoparticles exhibited the crystal tetragonal structure and the pH value of solu-tion had an important effect on the crystal structure and morphology of CeVO4 nanoparticles. Furthermore, the tribological properties of CeVO4 nanoparticles as additives in liquid paraffin were evaluated on a four-ball tester. The results indicated that the wear resistance was im-proved by the additive CeVO4 nanoparticles which exhibited very good antiwear and friction reduction performance in wear.
基金supported by National Natural Science Foundation of China(No.51502116)the Six Talents Peak Project in Jiangsu Province(No.2011-ZBZZ045)+2 种基金Natural Science Foundation of Jiangsu Province(No.BK20140557)Special Funding of China Postdoctoral Science Foundation(No.2016T90425)China Postdoctoral Science Foundation(No.2015M571682)
文摘The CeVO_4/graphitic C_3N_4 composites have exhibited much enhanced photocatalytic property for degrading methylene blue(MB) pollutant under visible light irradiation compared with single-phase g-C_3N_4 or CeVO_4. The composite S5 obtained from an optimized mass ratio(5%) of CeVO_4 to dicyanamide(DCDA) exhibits the highest photocatalytic activity. Here, ternary Ag/CeVO_4/g-C_3N_4 composites denoted as X%Ag/S5 were prepared by an ultrasonic precipitation method to improve the photocatalytic property of S5. The TEM images show that CeVO_4 and Ag nanoparticles are well distributed on the layered g-C_3N_4, which agree well with the XRD results. The UV spectra show that the 7%Ag/S5 sample has the widest absorption range and the enhanced absorption intensity under visible light irradiation. The corresponding band gap of 7%Ag/S5(2.5 eV) is much lower than that of S5(2.65 eV). The corresponding k value of 7%Ag/S5 is much higher than those of g-C_3N_4 and CeVO_4. The degradation experiments for MB solution suggest that the 7%Ag/S5 sample has the optimal photocatalytic performance, which can degrade MB solution completely within 120 min. The enhanced photocatalytic property of the composites is ascribed to not only the effect of heterojunction structure, but also the surface plasma resonance effect of Ag nanoparticles.
基金financial support by the Open Project Program of the State Key Laboratory of Solid Lu-brication, Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences (0804)
文摘Selective-controlled structure and shape of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce（NO3）3·6H2O.The resulting products were characterized by X-ray powder diffraction （XRD）,field emission scanning electron microscopy （FESEM） and energy dispersive spectroscopy （EDS）.The influence of hydrothermal temperature,precursor solution concentration on the crystal and morphology of products were further studied.The results showed that the as-synthesized products exhibited pure single-crystal CeVO4 nanoparticles with tetragonal structure.The hydrothermal temperature and precursor solution concentration had important effects on the formation of CeVO4 nanoparticles.Furthermore,the growth mechanism of CeVO4 nanoparticles was explained with Ostwald ripening mechanism.
基金Center of Excellence in Materials Science and Technology,Chiang Mai University,for financial support under the administration of Materials Science Research Center,Faculty of Science,Chiang Mai University,Thailand。
文摘Pure CeVO_(4) and Dy-doped CeVO_(4) nanorods containing different weight contents of Dy dopant were synthesized by hydrothermal method.Effect of Dy dopant on photodegradation of methylene blue(MB)and rhodamine B(RhB) was evaluated under UV light irradiation within 80 min.Pure CeVO_(4) and Dydoped CeVO_(4) nanorods were characterized by X-ray diffraction(XRD),Raman spectroscopy,transmission electron microscopy(TEM) and UV-visible spectroscopy.In this research,CeVO_(4) nanorods are tetragonal phase with the detection of main peak shift after being doped with Dy.The length of nanorods is deceased from 50 to 200 nm for pure CeVO_(4) to 50-100 nm for 3% Dy-doped CeVO_(4).Photodegradation of MB and RhB by CeVO_(4) nanorods under UV light irradiation is improved by Dy-dopant that plays the role in accepting electrons and reducing electron-hole recombination.MB and RhB solutions degraded by 3% Dy-doped CeVO_(4) nanorods was 94% and 93% within 80 min,respectively.
