Achieving a strong redox ability and high visible-light absorption ability in a single semiconductor material is difficult.Designing a heterojunction between two semiconductor materials is a feasible method.The new st...Achieving a strong redox ability and high visible-light absorption ability in a single semiconductor material is difficult.Designing a heterojunction between two semiconductor materials is a feasible method.The new step(S-scheme)heterojunction can effectively promote the separation and trans-fer of photogenerated electron-hole pairs and retain strong redox ability.We designed and pre-pared a Cd Se_(0.8)S_(0.2)-diethylenetriamine(DETA)/Sn Nb_(2)O_(6)heterostructure material via the sol-vothermal method.When Cd Se_(0.8)S_(0.2)-DETA and Sn Nb_(2)O_(6)form an S-scheme heterojunction,30%Cd Se_(0.8)S_(0.2)-DETA/Sn Nb_(2)O_(6)exhibits the highest CO production rate(17.31μmol·g^(-1)·h^(-1)),which is factors of 2.8 and 4.8 higher than that of traditional solvothermal Sn Nb_(2)O_(6)(6.2μmol·g^(-1)·h^(-1))and Cd Se_(0.8)S_(0.2)-DETA(3.6μmol·g^(-1)·h^(-1)),respectively.X-ray photoelectron spectroscopy characterization data provided evidence that the transfer pathway of space charge in the CO_(2)reduction process was in accordance with the S-scheme.This research provides a simple strategy through which one can optimize the band structure to promote the separation of photogenerated carriers and achieve a high efficiency of CO_(2)reduction.展开更多
Solution-phase hydrogen reduction(Sp HR)was introduced into V_(2)O_(3)preparation to overcome disadvantages of traditional reduction roasting,which include a long process,high energy consumption,and generation of poll...Solution-phase hydrogen reduction(Sp HR)was introduced into V_(2)O_(3)preparation to overcome disadvantages of traditional reduction roasting,which include a long process,high energy consumption,and generation of pollution.The research mainly focuses onφ-pH diagrams and kinetics of SpHR.Thermodynamic analysis ofφ-pH diagrams for the V-H_(2)O system demonstrates that V_(2)O_(3)preparation via Sp HR requires a high temperature,a high vanadium concentration,and sufficient hydrogen in acidic solution.Kinetic analyses show that the activation energy of V_(2)O_(3)preparation via SpHR is 38.0679 k J/mol,indicating that the reduction is controlled by a combination of interfacial chemical reaction and internal diffusion.Effects of H;partial pressure(slope K=0.05246)on the reaction rate is not as significant as the vanadium concentration(K=1.58872).V_(2)O_(3)crystals with a purity of 99.59%and a vanadium precipitation rate of 99.83%were obtained under the following conditions:pH=5-6,c(V_(2)O_(3))=0.5 mol/L,p(H;)=4 MPa,m(PdCl;)=10 mg,T=250℃,and t=2.5 h.展开更多
Non-stoichiometric W_(18)O_(49)(WO)prepared by solvothermal method has excellent NIR absorption due to the localized surface plasmon resonance effect caused by oxygen vacancies.This has great potential in the field of...Non-stoichiometric W_(18)O_(49)(WO)prepared by solvothermal method has excellent NIR absorption due to the localized surface plasmon resonance effect caused by oxygen vacancies.This has great potential in the field of using sunlight to convert carbon dioxide into organic fuels.In addition,through the amination of CdSe,the one-dimensional/two-dimensional step-scheme(S-scheme)WO/CdSe-diethylenetriamine(WO/CdSe-D)photocatalyst with electron transmission channels driven by visible light to NIR light is constructed by microwave solvothermal method.The LSPR of WO and the synergistic effect of coupling semiconductors to construct S-scheme heterojunctions can improve light utilization and achieve efficient charge carrier transfer efficiency.The optimized photocatalyst of 35%WO/CdSe-D has the best CO_(2) reduction performance compared to WO and CdSe-D,and the yield is 25.37μmol h^(–1) g^(–1).X-ray photoelectron spectroscopy was used to verify the charge transfer path of the S-scheme WO/CdSe-D heterojunction.This work provides a possibility for the application of non-stoichiometric oxides rich in oxygen vacancies in the field of photocatalytic CO_(2) reduction.展开更多
文摘Achieving a strong redox ability and high visible-light absorption ability in a single semiconductor material is difficult.Designing a heterojunction between two semiconductor materials is a feasible method.The new step(S-scheme)heterojunction can effectively promote the separation and trans-fer of photogenerated electron-hole pairs and retain strong redox ability.We designed and pre-pared a Cd Se_(0.8)S_(0.2)-diethylenetriamine(DETA)/Sn Nb_(2)O_(6)heterostructure material via the sol-vothermal method.When Cd Se_(0.8)S_(0.2)-DETA and Sn Nb_(2)O_(6)form an S-scheme heterojunction,30%Cd Se_(0.8)S_(0.2)-DETA/Sn Nb_(2)O_(6)exhibits the highest CO production rate(17.31μmol·g^(-1)·h^(-1)),which is factors of 2.8 and 4.8 higher than that of traditional solvothermal Sn Nb_(2)O_(6)(6.2μmol·g^(-1)·h^(-1))and Cd Se_(0.8)S_(0.2)-DETA(3.6μmol·g^(-1)·h^(-1)),respectively.X-ray photoelectron spectroscopy characterization data provided evidence that the transfer pathway of space charge in the CO_(2)reduction process was in accordance with the S-scheme.This research provides a simple strategy through which one can optimize the band structure to promote the separation of photogenerated carriers and achieve a high efficiency of CO_(2)reduction.
基金financially supported by the National Key R&D Program of China(No.2020YFC1909700)Outstanding Young and Middle-aged Science and Technology Innovation Team Project of Hubei Province,China(No.T201802)the National Natural Science Foundation of China(No.52004187)。
文摘Solution-phase hydrogen reduction(Sp HR)was introduced into V_(2)O_(3)preparation to overcome disadvantages of traditional reduction roasting,which include a long process,high energy consumption,and generation of pollution.The research mainly focuses onφ-pH diagrams and kinetics of SpHR.Thermodynamic analysis ofφ-pH diagrams for the V-H_(2)O system demonstrates that V_(2)O_(3)preparation via Sp HR requires a high temperature,a high vanadium concentration,and sufficient hydrogen in acidic solution.Kinetic analyses show that the activation energy of V_(2)O_(3)preparation via SpHR is 38.0679 k J/mol,indicating that the reduction is controlled by a combination of interfacial chemical reaction and internal diffusion.Effects of H;partial pressure(slope K=0.05246)on the reaction rate is not as significant as the vanadium concentration(K=1.58872).V_(2)O_(3)crystals with a purity of 99.59%and a vanadium precipitation rate of 99.83%were obtained under the following conditions:pH=5-6,c(V_(2)O_(3))=0.5 mol/L,p(H;)=4 MPa,m(PdCl;)=10 mg,T=250℃,and t=2.5 h.
文摘Non-stoichiometric W_(18)O_(49)(WO)prepared by solvothermal method has excellent NIR absorption due to the localized surface plasmon resonance effect caused by oxygen vacancies.This has great potential in the field of using sunlight to convert carbon dioxide into organic fuels.In addition,through the amination of CdSe,the one-dimensional/two-dimensional step-scheme(S-scheme)WO/CdSe-diethylenetriamine(WO/CdSe-D)photocatalyst with electron transmission channels driven by visible light to NIR light is constructed by microwave solvothermal method.The LSPR of WO and the synergistic effect of coupling semiconductors to construct S-scheme heterojunctions can improve light utilization and achieve efficient charge carrier transfer efficiency.The optimized photocatalyst of 35%WO/CdSe-D has the best CO_(2) reduction performance compared to WO and CdSe-D,and the yield is 25.37μmol h^(–1) g^(–1).X-ray photoelectron spectroscopy was used to verify the charge transfer path of the S-scheme WO/CdSe-D heterojunction.This work provides a possibility for the application of non-stoichiometric oxides rich in oxygen vacancies in the field of photocatalytic CO_(2) reduction.
