In this study,a ZnxCd1-xS solid solution was successfully synthesized using a hydrothermal method.MoS2 serving as a co-catalyst for hydrogen evolution was also prepared through a one-pot hydrothermal method.The struct...In this study,a ZnxCd1-xS solid solution was successfully synthesized using a hydrothermal method.MoS2 serving as a co-catalyst for hydrogen evolution was also prepared through a one-pot hydrothermal method.The structures,morphology,chemical states,and optical properties were characterized using powder X-ray diffraction,scanning electron microscopy,high-angle annular dark field-scanning transmission electron microscopy,elemental mapping,X-ray photoelectron spectroscopy,and UV-Vis diffuse reflection spectroscopy.Visible-light-driven photocatalytic experiments were conducted to simultaneously achieve hydrogen production and amoxicillin antibiotic wastewater degradation.The results indicated 8%MoS2/ZnxCd1-xS achieves the best photocatalytic performance.The ZnxCd1-xS samples illustrated a superior performance to that of CdS,which can be attributed to a thermodynamic improvement.Based on the results of PL and TRPL analyses,the enhancement of the hydrogen production mechanisms can be ascribed to the prolonged separation process of the photocarriers.Furthermore,the degradation results were analyzed using the HPLC method and the possible degradation pathways were determined through the HPLC-MS techniques.展开更多
Step-scheme(S-scheme)heterojunctions in photocatalysts can provide novel and practical insight on promoting photogenerated carrier separation.The latter is critical in controlling the overall efficiency in one-step ph...Step-scheme(S-scheme)heterojunctions in photocatalysts can provide novel and practical insight on promoting photogenerated carrier separation.The latter is critical in controlling the overall efficiency in one-step photoexcitation systems.In this study,a nanosized BiVO4/Bi0.6Y0.4VO4 solid solution was prepared by a coprecipitation method following with hydrothermal or calcination processes.The S-scheme heterojunction was fabricated by in-situ pressure-induced transformations of bismuth vanadate from the tetragonal zircon phase to the monoclinic scheelite phase,which led to the formation of BiVO4 nanoparticles with a diameter of approximately 5 nm on the surface of BiVO_(4)/Bi_(0.6)Y_(0.4)VO_(4)/Bi_(0.6)Y_(0.4)VO_(4) with S-scheme heterojunctions showed significantly enhanced photocatalytic overall water splitting activity compared with using bare BiVO_(4)/Bi_(0.6)Y_(0.4)VO_(4).Characterization of the carrier dynamics demonstrated that a superior carrier separation through S-type heterojunctions might have caused the enhanced overall water splitting(OWS)activity.Surface photovoltage spectra and the results of selective photodeposition experiments indicated that the photogenerated holes mainly migrated to the BiVO4 nanoparticles in the heterojunction.This confirmed that the charge transfer route corresponds to an S-scheme rather than a type-II heterojunction mechanism under light illumination.This study presents a facile and efficient strategy to construct S-scheme heterojunctions through a pressure-induced phase transition.The results demonstrated that S-scheme junctions composed of different crystalline phases can boost the carrier separation capacity and eventually improve the photocatalytic OWS activity.展开更多
Developing low-cost and high-efficient noble-metal-free cocatalysts has been a challenge to achieve economic hydrogen production.In this work,molybdenum oxides(MoO3-x)were in situ loaded on polymer carbon nitride(PCN)...Developing low-cost and high-efficient noble-metal-free cocatalysts has been a challenge to achieve economic hydrogen production.In this work,molybdenum oxides(MoO3-x)were in situ loaded on polymer carbon nitride(PCN)via a simple one-pot impregnation-calcination approach.Different from post-impregnation method,intimate coupling interface between high-dispersed ultra-small MoO3-xnanocrystal and PCN was successfully formed during the in situ growth process.The MoO3-x-PCN-X(X=1,2,3,4)photocatalyst without noble platinum(Pt)finally exhibited enhanced photocatalytic hydrogen performance under visible light irradiation(λ>420 nm),with the highest hydrogen evolution rate of 15.6μmol/h,which was more than 3 times that of bulk PCN.Detailed structure-performance revealed that such improvement in visible-light hydrogen production activity originated from the intimate interfacial interaction between high-dispersed ultra-small MoO3-xnanocrystal and polymer carbon nitride as well as efficient charge carriers transfer brought by Schottky junction formed.展开更多
基金the National Natural Science Foundation of China (21773153)the National Key Basic Research and Development Program (2018YFB1502001) for the financial supportthe Funding support from Centre of Hydrogen Science, Shanghai Jiao Tong University, China~~
文摘In this study,a ZnxCd1-xS solid solution was successfully synthesized using a hydrothermal method.MoS2 serving as a co-catalyst for hydrogen evolution was also prepared through a one-pot hydrothermal method.The structures,morphology,chemical states,and optical properties were characterized using powder X-ray diffraction,scanning electron microscopy,high-angle annular dark field-scanning transmission electron microscopy,elemental mapping,X-ray photoelectron spectroscopy,and UV-Vis diffuse reflection spectroscopy.Visible-light-driven photocatalytic experiments were conducted to simultaneously achieve hydrogen production and amoxicillin antibiotic wastewater degradation.The results indicated 8%MoS2/ZnxCd1-xS achieves the best photocatalytic performance.The ZnxCd1-xS samples illustrated a superior performance to that of CdS,which can be attributed to a thermodynamic improvement.Based on the results of PL and TRPL analyses,the enhancement of the hydrogen production mechanisms can be ascribed to the prolonged separation process of the photocarriers.Furthermore,the degradation results were analyzed using the HPLC method and the possible degradation pathways were determined through the HPLC-MS techniques.
文摘Step-scheme(S-scheme)heterojunctions in photocatalysts can provide novel and practical insight on promoting photogenerated carrier separation.The latter is critical in controlling the overall efficiency in one-step photoexcitation systems.In this study,a nanosized BiVO4/Bi0.6Y0.4VO4 solid solution was prepared by a coprecipitation method following with hydrothermal or calcination processes.The S-scheme heterojunction was fabricated by in-situ pressure-induced transformations of bismuth vanadate from the tetragonal zircon phase to the monoclinic scheelite phase,which led to the formation of BiVO4 nanoparticles with a diameter of approximately 5 nm on the surface of BiVO_(4)/Bi_(0.6)Y_(0.4)VO_(4)/Bi_(0.6)Y_(0.4)VO_(4) with S-scheme heterojunctions showed significantly enhanced photocatalytic overall water splitting activity compared with using bare BiVO_(4)/Bi_(0.6)Y_(0.4)VO_(4).Characterization of the carrier dynamics demonstrated that a superior carrier separation through S-type heterojunctions might have caused the enhanced overall water splitting(OWS)activity.Surface photovoltage spectra and the results of selective photodeposition experiments indicated that the photogenerated holes mainly migrated to the BiVO4 nanoparticles in the heterojunction.This confirmed that the charge transfer route corresponds to an S-scheme rather than a type-II heterojunction mechanism under light illumination.This study presents a facile and efficient strategy to construct S-scheme heterojunctions through a pressure-induced phase transition.The results demonstrated that S-scheme junctions composed of different crystalline phases can boost the carrier separation capacity and eventually improve the photocatalytic OWS activity.
基金the National Natural Science Foundation of China(No.21872093)the National Key Research and Development Program of China(No.2018YFB1502001)the Center of Hydrogen Science of Shanghai Jiao Tong University。
文摘Developing low-cost and high-efficient noble-metal-free cocatalysts has been a challenge to achieve economic hydrogen production.In this work,molybdenum oxides(MoO3-x)were in situ loaded on polymer carbon nitride(PCN)via a simple one-pot impregnation-calcination approach.Different from post-impregnation method,intimate coupling interface between high-dispersed ultra-small MoO3-xnanocrystal and PCN was successfully formed during the in situ growth process.The MoO3-x-PCN-X(X=1,2,3,4)photocatalyst without noble platinum(Pt)finally exhibited enhanced photocatalytic hydrogen performance under visible light irradiation(λ>420 nm),with the highest hydrogen evolution rate of 15.6μmol/h,which was more than 3 times that of bulk PCN.Detailed structure-performance revealed that such improvement in visible-light hydrogen production activity originated from the intimate interfacial interaction between high-dispersed ultra-small MoO3-xnanocrystal and polymer carbon nitride as well as efficient charge carriers transfer brought by Schottky junction formed.
