Photocatalytic hydrogen evolution through water splitting holds tremendous promise for converting solar energy into a clean and renewable fuel source.However,the efficiency of photocatalysis is often hindered by poor ...Photocatalytic hydrogen evolution through water splitting holds tremendous promise for converting solar energy into a clean and renewable fuel source.However,the efficiency of photocatalysis is often hindered by poor light absorption,insufficient charge separation,and slow reaction kinetics of the photocatalysts.In this study,we designed and synthesized a novel S-scheme heterojunction comprising Ti_(3)C_(2)MXene,CdS nanorods,and nitrogen-doped carbon coated Cu_(2)O(Cu_(2)O@NC)core-shell nanoparticles.Ti_(3)C_(2)MXene as a cocatalyst enhances the light absorption and charge transfer of CdS nanorods.Simultaneously,the core-shell Cu_(2)O@NC nanoparticles establish a pathway for transferring photogenerated electrons and create a favorable band alignment for efficient hydrogen evolution.The synergistic effects of Ti_(3)C_(2)MXene and Cu_(2)O@NC on CdS nanorods result in multiple charge transfer channels and improved photocatalytic performance.The optimal hydrogen evolution rate of the Ti_(3)C_(2)-CdS-Cu_(2)O@NC S-scheme heterojunction photocatalyst is 7.4 times higher than that of pure CdS.Experimental techniques and DFT calculations were employed to explore the structure,morphology,optical properties,charge dynamics,and band structure of the heterojunction.The results revealed that the S-scheme mechanism effectively suppresses the recombination of photogenerated carriers and facilitates the separation and migration of photo-generated electrons and holes to the reaction sites.Furthermore,Ti_(3)C_(2)MXene provides abundant active sites essential for accelerating the surface H_(2)-evolution reaction kinetics.The Cu_(2)O@NC core-shell nanoparticles with a large surface area and high stability are closely adhered to CdS nanorods and establish an S-scheme internal electric field with CdS nanorods to drive charge separation.This investigation provides valuable insights into the rational design of CdS-based photocatalysts,enabling efficient hydrogen production by harnessing the robust kinetic driving force provided by the S-scheme heterojunctions.展开更多
The appropriate regulation of band structure is an effective strategy in constructing efficient photocatalytic systems.Present photocatalytic system mainly employs powder photocatalysts,which makes their recovery reli...The appropriate regulation of band structure is an effective strategy in constructing efficient photocatalytic systems.Present photocatalytic system mainly employs powder photocatalysts,which makes their recovery reliant on expensive separation processes and severely limits their industrial application.Herein,we constructed a novel CdS/Ni_(3)S_(2)heterostructure using free-standing and flexible nickel fiber paper as the matrix.The regulated energy band structure achieves effective electron–hole separation.The as-synthesized flexible photocatalyst exhibits considerable photocatalytic activity toward the H_(2)evolution reaction under visible-light irradiation,with an H_(2)production rate of5.63μmol·cm^(-2)·h^(-1)(14.1 mmol·g^(-1)cat·h^(-1)according to the catalyst loading content).Additionally,the otherwisewasted excited holes simultaneously drive organic transformations to yield value-added organic products,thus markedly improving the photocatalytic H_(2)evolution rate.Such a photocatalytic system is scaled up further,where a self-supported 20 cm×25 cm sample achieves a champion H_(2)production rate of 60-80μmol·h^(-1)under practical sun irradiation.This newly developed self-supported photocatalyst produces opportunities for practical solar H2production with biomass upgrading.展开更多
S-scheme heterojunctions have promising applications in photocatalytic CO_(2) reduction due to their unique structure and interfacial interactions,but improving their carrier separation efficiency and CO_(2) adsorptio...S-scheme heterojunctions have promising applications in photocatalytic CO_(2) reduction due to their unique structure and interfacial interactions,but improving their carrier separation efficiency and CO_(2) adsorption capacity remains a challenge.In this work,highly dispersed MOF-BiOBr/Mn_(0.2) Cd_(0.8) S(MOF-BiOBr/MCS)S-scheme heterojunctions with high photocatalytic CO_(2) reduction performance were constructed.The intimate contact between the MCS nano-spheres and the nanosheet-assembled MOF-BiOBr rods,driven by the internal electric field,accelerates the charge transfer along the S-scheme pathway.Moreover,the high specific surface area of MOFs is preserved to provide abundant active sites for reaction/adsorption.The formation of MOF-BiOBr/MCS S-scheme heterojunction is confirmed by theoretical calculations.The optimum MOF-BiOBr/MCS shows excellent activity in CO_(2) reduction,affording a high CO evolution rate of 60.59µmol h^(−1) g^(−1).The present work can inspire the exploration for the construction of effective heterostructure photocatalysts for photoreduction CO_(2).展开更多
Converting solar energy into chemical energy by artificial photosynthesis is promising in addressing the issues of the greenhouse effect and fossil fuel crisis.Herein,a novel photocatalyst,i.e.CdS/TiO_(2) hollow micro...Converting solar energy into chemical energy by artificial photosynthesis is promising in addressing the issues of the greenhouse effect and fossil fuel crisis.Herein,a novel photocatalyst,i.e.CdS/TiO_(2) hollow microspheres(HS),were dedicatedly designed to boost overall photocatalytic efficiency.TiO_(2) nanoparticles were in-situ decorated on the inside and outside the shell of Cd S HS,ensuring close contact between TiO_(2) and CdS.The CdS/TiO2 HS with abundant mesopores inside of the shell boost the light absorption via multiscattering effect as well as accessible to reactions in all directions.The heterojunction was scrutinized and the charge transfer across it was revealed by in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS).Ultimately,the charge transfer in this composite was determined to follow stepscheme mechanism,which not only facilitates the separation of charge carriers but also preserves strong redox ability.Benefited from the intimate linkage between Cd S and TiO_(2) and the favorable step-scheme heterojunction,enhanced photocatalytic CO_(2) reduction activity was accomplished.The CH4 yield rate of CdS/TiO_(2) reaches 27.85μmol g^(–1) h^(–1),which is 145.6 and 3.8 times higher than those of pristine CdS and TiO_(2),respectively.This work presents a novel insight into constructing step-scheme photocatalytic system with desirable performance.展开更多
基金National Natural Science Foundation of China(21975084,51672089)Natural Science Foundation of Guangdong Province(2021A1515010075)for their support
文摘Photocatalytic hydrogen evolution through water splitting holds tremendous promise for converting solar energy into a clean and renewable fuel source.However,the efficiency of photocatalysis is often hindered by poor light absorption,insufficient charge separation,and slow reaction kinetics of the photocatalysts.In this study,we designed and synthesized a novel S-scheme heterojunction comprising Ti_(3)C_(2)MXene,CdS nanorods,and nitrogen-doped carbon coated Cu_(2)O(Cu_(2)O@NC)core-shell nanoparticles.Ti_(3)C_(2)MXene as a cocatalyst enhances the light absorption and charge transfer of CdS nanorods.Simultaneously,the core-shell Cu_(2)O@NC nanoparticles establish a pathway for transferring photogenerated electrons and create a favorable band alignment for efficient hydrogen evolution.The synergistic effects of Ti_(3)C_(2)MXene and Cu_(2)O@NC on CdS nanorods result in multiple charge transfer channels and improved photocatalytic performance.The optimal hydrogen evolution rate of the Ti_(3)C_(2)-CdS-Cu_(2)O@NC S-scheme heterojunction photocatalyst is 7.4 times higher than that of pure CdS.Experimental techniques and DFT calculations were employed to explore the structure,morphology,optical properties,charge dynamics,and band structure of the heterojunction.The results revealed that the S-scheme mechanism effectively suppresses the recombination of photogenerated carriers and facilitates the separation and migration of photo-generated electrons and holes to the reaction sites.Furthermore,Ti_(3)C_(2)MXene provides abundant active sites essential for accelerating the surface H_(2)-evolution reaction kinetics.The Cu_(2)O@NC core-shell nanoparticles with a large surface area and high stability are closely adhered to CdS nanorods and establish an S-scheme internal electric field with CdS nanorods to drive charge separation.This investigation provides valuable insights into the rational design of CdS-based photocatalysts,enabling efficient hydrogen production by harnessing the robust kinetic driving force provided by the S-scheme heterojunctions.
基金supported by the National Natural Science Foundation of China(Nos.51972147,52022037 and 52202366)Taishan Scholars Project Special Funds(No.tsqn201812083),the Innovative Team Project of Jinan(No.2021GXRC019)+1 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2019YQ20,ZR2021QE011,ZR2021JQ15 and ZR2022YQ42)the King Abdullah University of Science and Technology(KAUST)。
文摘The appropriate regulation of band structure is an effective strategy in constructing efficient photocatalytic systems.Present photocatalytic system mainly employs powder photocatalysts,which makes their recovery reliant on expensive separation processes and severely limits their industrial application.Herein,we constructed a novel CdS/Ni_(3)S_(2)heterostructure using free-standing and flexible nickel fiber paper as the matrix.The regulated energy band structure achieves effective electron–hole separation.The as-synthesized flexible photocatalyst exhibits considerable photocatalytic activity toward the H_(2)evolution reaction under visible-light irradiation,with an H_(2)production rate of5.63μmol·cm^(-2)·h^(-1)(14.1 mmol·g^(-1)cat·h^(-1)according to the catalyst loading content).Additionally,the otherwisewasted excited holes simultaneously drive organic transformations to yield value-added organic products,thus markedly improving the photocatalytic H_(2)evolution rate.Such a photocatalytic system is scaled up further,where a self-supported 20 cm×25 cm sample achieves a champion H_(2)production rate of 60-80μmol·h^(-1)under practical sun irradiation.This newly developed self-supported photocatalyst produces opportunities for practical solar H2production with biomass upgrading.
基金supported by the National Natural Science Foundation of China(Nos.22278169 and 51973078)the Excellent scientific research and innovation team of Education Department of Anhui Province(No.2022AH010028)+1 种基金the Major projects of Education Department of Anhui Province(No.2022AH040068)the Key Foundation of Educational Commission of Anhui Province(No.2022AH050396).
文摘S-scheme heterojunctions have promising applications in photocatalytic CO_(2) reduction due to their unique structure and interfacial interactions,but improving their carrier separation efficiency and CO_(2) adsorption capacity remains a challenge.In this work,highly dispersed MOF-BiOBr/Mn_(0.2) Cd_(0.8) S(MOF-BiOBr/MCS)S-scheme heterojunctions with high photocatalytic CO_(2) reduction performance were constructed.The intimate contact between the MCS nano-spheres and the nanosheet-assembled MOF-BiOBr rods,driven by the internal electric field,accelerates the charge transfer along the S-scheme pathway.Moreover,the high specific surface area of MOFs is preserved to provide abundant active sites for reaction/adsorption.The formation of MOF-BiOBr/MCS S-scheme heterojunction is confirmed by theoretical calculations.The optimum MOF-BiOBr/MCS shows excellent activity in CO_(2) reduction,affording a high CO evolution rate of 60.59µmol h^(−1) g^(−1).The present work can inspire the exploration for the construction of effective heterostructure photocatalysts for photoreduction CO_(2).
基金financially supported by the National Natural Science Foundation of China(NSFC)(Nos.51872220,51932007,51961135303,21871217,U1905215 and U1705251)the National Key Research and Development Program of China(No.2018YFB1502001)the Fundamental Research Funds for the Central Universities(No.WUT:2019IVB050)。
文摘Converting solar energy into chemical energy by artificial photosynthesis is promising in addressing the issues of the greenhouse effect and fossil fuel crisis.Herein,a novel photocatalyst,i.e.CdS/TiO_(2) hollow microspheres(HS),were dedicatedly designed to boost overall photocatalytic efficiency.TiO_(2) nanoparticles were in-situ decorated on the inside and outside the shell of Cd S HS,ensuring close contact between TiO_(2) and CdS.The CdS/TiO2 HS with abundant mesopores inside of the shell boost the light absorption via multiscattering effect as well as accessible to reactions in all directions.The heterojunction was scrutinized and the charge transfer across it was revealed by in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS).Ultimately,the charge transfer in this composite was determined to follow stepscheme mechanism,which not only facilitates the separation of charge carriers but also preserves strong redox ability.Benefited from the intimate linkage between Cd S and TiO_(2) and the favorable step-scheme heterojunction,enhanced photocatalytic CO_(2) reduction activity was accomplished.The CH4 yield rate of CdS/TiO_(2) reaches 27.85μmol g^(–1) h^(–1),which is 145.6 and 3.8 times higher than those of pristine CdS and TiO_(2),respectively.This work presents a novel insight into constructing step-scheme photocatalytic system with desirable performance.
