Porous hollow microspheres of bismuth vanadate(BiVO_4) were successfully synthesized with the assistances of ethylenediamine tetraacetic(EDTA) and sodium dodecylbenzene sulfonate(SDBS) via hydrothermal method.The as-p...Porous hollow microspheres of bismuth vanadate(BiVO_4) were successfully synthesized with the assistances of ethylenediamine tetraacetic(EDTA) and sodium dodecylbenzene sulfonate(SDBS) via hydrothermal method.The as-prepared BiVO_4 samples were characterized by X-ray diffraction(XRD),field-emission scanning electron microscopy(FE-SEM) and UV-vis diffuse reflectance spectra(DRS).It was found that the ratio of EDTA and SDBS had a significant impact on the crystalline structure,size and morphology of BiVO_4 photocatalyst.The crystal phase could be adjusted by changing the mass ratio of EDTA and SDBS.The photocatalytic activities of different BiVO_4 samples were investigated through the degradation of RhB in the presence of H_2O_2 under visible light irradiation.The results indicated that the photocatalytic performance of the BiVO_4 microstructures was greatly influenced by the porous structure,morphology and band gap.The BiVO_4 sample prepared with the EDTA and SDBS ratio of 2:1 and total amount of 1.5 g have shown superior photocatalytic performance for its unique morphology,good porous structure and low band gap energy.展开更多
We report a photoelectrochemical investigation of BiVO4 photoanodes prepared by successive ionic layer adsorption and reaction(SILAR),a facile method that yields uniform nanoporous films.After characterization of the ...We report a photoelectrochemical investigation of BiVO4 photoanodes prepared by successive ionic layer adsorption and reaction(SILAR),a facile method that yields uniform nanoporous films.After characterization of the phase,morphology,composition,and optical properties of the prepared films,the efficiencies of charge separation(ηsep)and water oxidation(ηox)in solar water splitting cells employing these photoanodes were estimated following a previously reported procedure.Unexpected wavelength and illumination direction dependencies were discovered in the derived efficiencies,casting doubt on the validity of the analysis.An alternative approach using a diffusion–reaction model that explicitly considers the efficiency of electron collection resolved the discrepancies and explained the illumination direction dependence of the photocurrent.Electron diffusion lengths(Ln)of 0.45μm and 0.55μm were derived for pristine and cobalt phosphate(Co-Pi)modified BiVO4,respectively,which are much shorter than the film thickness of^2.1μm.The Co-Pi treatment also increasedηoxfrom 0.86 to^1,which is the main reason for the overall performance enhancement caused by adding Co-Pi.These findings suggest that there is little scope for improving the performance of SILAR-deposited BiVO4 photoanodes by further catalyzing water oxidation,but enhanced performance is achievable if electron transport can be improved.展开更多
Oxygen vacancies in oxygen evolution cocatalysts(OECs)can significantly improve the photoelectrochemical(PEC)water splitting performance of photoanodes.However,OECs with abundant oxygen vacancies have a poor stability...Oxygen vacancies in oxygen evolution cocatalysts(OECs)can significantly improve the photoelectrochemical(PEC)water splitting performance of photoanodes.However,OECs with abundant oxygen vacancies have a poor stability when exposing to the highly-oxidizing photogenerated holes.Herein,we partly fill oxygen vacancies in a MnCo_(2)O_(x) OEC with N atoms by a combined electrodeposition and sol-gel method,which dramatically improves both photocurrent density and stability of a BiVO_(4) photoanode.The optimized N filled oxygen vacancy-rich MnCo_(2)O_(x)/BiVO_(4) photoanode(3 at.%of N)exhibits an outstanding photocurrent density of 6.5 mA·cm^(-2) at 1.23 VRHE under AM 1.5 G illumination(100 mW·cm^(-2)),and an excellent stability of over 150 h.Systematic characterizations and theoretical calculations demonstrate that N atoms stabilize the defect structure and modulate the surface electron distribution,which significantly enhances the stability and further increases the photocurrent density.Meanwhile,other heteroatoms such as carbon,phosphorus,and sulfur are confirmed to have similar effects on improving PEC water splitting performance of photoanodes.展开更多
Photoelectrochemical(PEC)technology is considered to be a promising approach for solar-driven hydrogen production with zero emissions.Bismuth vanadate(BiVO_(4))is a kind of photocatalytic material with strong photoact...Photoelectrochemical(PEC)technology is considered to be a promising approach for solar-driven hydrogen production with zero emissions.Bismuth vanadate(BiVO_(4))is a kind of photocatalytic material with strong photoactivity in the visible light region and appropriate band gap for PEC water splitting.However,the solar-to-hydrogen efficiency(STH)of BiVO_(4)is far away from the 10%target needed for practical application due to its poor charge separation ability.Therefore,this review attempts to summarize the strategies for improving the photocurrent density and especially hydrogen production of BiVO_(4)materials through PEC techniques in the last three years,such as doping nonmetal and metal elements,depositing noble metals,constructing heterojunctions,coupling with carbon and metalorganic framework(MOF)materials to further enhance the PEC performance of BiVO_(4)photoanode.This review aims to serve as a general guideline to fabricate highly efficient BiVO_(4)-based materials for PEC water splitting.展开更多
A series of H3PW12O40/BiVO4 composite with different H3PW12O40 loadings were prepared using a hydrothermal and impregnation method. The prepared composites were characterized by XRD, Raman, SEM, XPS, and DRS technique...A series of H3PW12O40/BiVO4 composite with different H3PW12O40 loadings were prepared using a hydrothermal and impregnation method. The prepared composites were characterized by XRD, Raman, SEM, XPS, and DRS techniques. The bandgap of the composite was narrower compared with the as-prepared pure BiVO4 . As a novel photocatalytic material, the photocatalytic performance of the H3PW12O40/BiVO4 composite was investigated by the degradation of methylene blue (MB) dye solution under visible light irradiation and compared with that of pure BiVO4 . The results revealed that the introduction of H3PW12O40 could improve the photocatalytic performance and different concentrations of H3PW12O40 resulted in different photocatalytic activities. The highest activity was obtained by the sample with a loading HPW concentration of 10 wt%. The reason for the enhanced photocatalytic activities of H3PW12O40/BiVO4 samples was also discussed in this paper. Moreover, the H3PW12O40/BiVO4 composites retained the catalytic activity after four repeated experiments.展开更多
基金National Natural Science Foundations of China(Nos.51178093,51208086)Central University Project,China(No.2232013D3-10)
文摘Porous hollow microspheres of bismuth vanadate(BiVO_4) were successfully synthesized with the assistances of ethylenediamine tetraacetic(EDTA) and sodium dodecylbenzene sulfonate(SDBS) via hydrothermal method.The as-prepared BiVO_4 samples were characterized by X-ray diffraction(XRD),field-emission scanning electron microscopy(FE-SEM) and UV-vis diffuse reflectance spectra(DRS).It was found that the ratio of EDTA and SDBS had a significant impact on the crystalline structure,size and morphology of BiVO_4 photocatalyst.The crystal phase could be adjusted by changing the mass ratio of EDTA and SDBS.The photocatalytic activities of different BiVO_4 samples were investigated through the degradation of RhB in the presence of H_2O_2 under visible light irradiation.The results indicated that the photocatalytic performance of the BiVO_4 microstructures was greatly influenced by the porous structure,morphology and band gap.The BiVO_4 sample prepared with the EDTA and SDBS ratio of 2:1 and total amount of 1.5 g have shown superior photocatalytic performance for its unique morphology,good porous structure and low band gap energy.
基金Universiti Brunei Darussalam through grant numbers UBD/RSCH/1.4/FICBF(b)/2018/009 and UBD/PNC2/2/RG/1(313).
文摘We report a photoelectrochemical investigation of BiVO4 photoanodes prepared by successive ionic layer adsorption and reaction(SILAR),a facile method that yields uniform nanoporous films.After characterization of the phase,morphology,composition,and optical properties of the prepared films,the efficiencies of charge separation(ηsep)and water oxidation(ηox)in solar water splitting cells employing these photoanodes were estimated following a previously reported procedure.Unexpected wavelength and illumination direction dependencies were discovered in the derived efficiencies,casting doubt on the validity of the analysis.An alternative approach using a diffusion–reaction model that explicitly considers the efficiency of electron collection resolved the discrepancies and explained the illumination direction dependence of the photocurrent.Electron diffusion lengths(Ln)of 0.45μm and 0.55μm were derived for pristine and cobalt phosphate(Co-Pi)modified BiVO4,respectively,which are much shorter than the film thickness of^2.1μm.The Co-Pi treatment also increasedηoxfrom 0.86 to^1,which is the main reason for the overall performance enhancement caused by adding Co-Pi.These findings suggest that there is little scope for improving the performance of SILAR-deposited BiVO4 photoanodes by further catalyzing water oxidation,but enhanced performance is achievable if electron transport can be improved.
基金The authors would like to acknowledge the financial support from National Natural Science Foundation of China(No.52002328)Shenzhen Science and Technology Program(No.JCYJ20220530161615035)+1 种基金the Practice and Innovation Funds for Graduate Students of Northwestern Polytechnical University(No.PF2023151)the Fundamental Research Funds for the Central Universities,and material characterizations from the Analytical&Testing Center of Northwestern Polytechnical University.
文摘Oxygen vacancies in oxygen evolution cocatalysts(OECs)can significantly improve the photoelectrochemical(PEC)water splitting performance of photoanodes.However,OECs with abundant oxygen vacancies have a poor stability when exposing to the highly-oxidizing photogenerated holes.Herein,we partly fill oxygen vacancies in a MnCo_(2)O_(x) OEC with N atoms by a combined electrodeposition and sol-gel method,which dramatically improves both photocurrent density and stability of a BiVO_(4) photoanode.The optimized N filled oxygen vacancy-rich MnCo_(2)O_(x)/BiVO_(4) photoanode(3 at.%of N)exhibits an outstanding photocurrent density of 6.5 mA·cm^(-2) at 1.23 VRHE under AM 1.5 G illumination(100 mW·cm^(-2)),and an excellent stability of over 150 h.Systematic characterizations and theoretical calculations demonstrate that N atoms stabilize the defect structure and modulate the surface electron distribution,which significantly enhances the stability and further increases the photocurrent density.Meanwhile,other heteroatoms such as carbon,phosphorus,and sulfur are confirmed to have similar effects on improving PEC water splitting performance of photoanodes.
基金financially supported by the National Natural Science Foundation of China(Nos.21663027,21808189)the Fundamental Research Funds for the Central Universities of Chang’an University(No.300102299304)the Natural Science Basic Research Fund of Shaanxi Province(No.2020JZ20)。
文摘Photoelectrochemical(PEC)technology is considered to be a promising approach for solar-driven hydrogen production with zero emissions.Bismuth vanadate(BiVO_(4))is a kind of photocatalytic material with strong photoactivity in the visible light region and appropriate band gap for PEC water splitting.However,the solar-to-hydrogen efficiency(STH)of BiVO_(4)is far away from the 10%target needed for practical application due to its poor charge separation ability.Therefore,this review attempts to summarize the strategies for improving the photocurrent density and especially hydrogen production of BiVO_(4)materials through PEC techniques in the last three years,such as doping nonmetal and metal elements,depositing noble metals,constructing heterojunctions,coupling with carbon and metalorganic framework(MOF)materials to further enhance the PEC performance of BiVO_(4)photoanode.This review aims to serve as a general guideline to fabricate highly efficient BiVO_(4)-based materials for PEC water splitting.
基金the Foundation of State Key Laboratory of Pollution Control and Resource Reuse of Chinathe China Postdoctoral Science Foundation funded project (2012M511254)+3 种基金the National Natural Science Foundation of China (51008154)the Natural Science Research Project of Jiangsu Province's Education Department (12KJD610004)the Scientific Innovation Research Foundation of Graduate Student of Jiangsu Province (CXZZ12-0063)the Scientific Research Foundation of Graduate Student of Nanjing University (2012CL10)
文摘A series of H3PW12O40/BiVO4 composite with different H3PW12O40 loadings were prepared using a hydrothermal and impregnation method. The prepared composites were characterized by XRD, Raman, SEM, XPS, and DRS techniques. The bandgap of the composite was narrower compared with the as-prepared pure BiVO4 . As a novel photocatalytic material, the photocatalytic performance of the H3PW12O40/BiVO4 composite was investigated by the degradation of methylene blue (MB) dye solution under visible light irradiation and compared with that of pure BiVO4 . The results revealed that the introduction of H3PW12O40 could improve the photocatalytic performance and different concentrations of H3PW12O40 resulted in different photocatalytic activities. The highest activity was obtained by the sample with a loading HPW concentration of 10 wt%. The reason for the enhanced photocatalytic activities of H3PW12O40/BiVO4 samples was also discussed in this paper. Moreover, the H3PW12O40/BiVO4 composites retained the catalytic activity after four repeated experiments.
