The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS...The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS QDs and hollow nanotube In_(2)O_(3)is successfully achieved using an electrostatic self-assembly method.Under visible light irradiation,all CdS-In_(2)O_(3)composites exhibit higher hydrogen evolution efficiency compared to pure CdS QDs.Notably,the photocatalytic H_(2)evolution rate of the optimal CdS-7%In_(2)O_(3)composite is determined to be 2258.59μmol g^(−1)h^(−1),approximately 12.3 times higher than that of pure CdS.The cyclic test indicates that the CdS-In_(2)O_(3)composite maintains considerable activity even after 5 cycles,indicating its excellent stability.In situ X-ray photoelectron spectroscopy and density functional theory calculations confirm that carrier migration in CdS-In_(2)O_(3)composites adheres to a typical S-scheme heterojunction mechanism.Additionally,a series of characterizations demonstrate that the formation of S-scheme heterojunctions between In_(2)O_(3)and CdS inhibits charge recombination and accelerates the separation and migration of photogenerated carriers in the CdS QDs,thus achieving enhanced photocatalytic performance.This work elucidates the pivotal role of S-scheme heterojunctions in photocatalytic H_(2)production and offers novel insights into the construction of effective composite photocatalysts.展开更多
Hydrogen peroxide(H_(2)O_(2)),an environmentally friendly chemical with high value,is extensively used in industrial production and daily life.However,the traditional anthraquinone method for H_(2)O_(2) production is ...Hydrogen peroxide(H_(2)O_(2)),an environmentally friendly chemical with high value,is extensively used in industrial production and daily life.However,the traditional anthraquinone method for H_(2)O_(2) production is associated with a highly energy-consuming and heavily polluting process.Solor-driven photocatalytic evolution of H_(2)O_(2) is a promising,eco-friendly,and energy-efficient strategy that holds great potential to substitute the traditional approach.Here,a ternary photocatalyst,NiS/CdS/Halloysite nanotubes(NiS/CdS/HNTs)is designed and prepared with an earth-abundant clay mineral HNTs as the support and NiS as a co-catalyst.The pivotal roles of HNTs and NiS in the photocatalytic process are elucidated by experiments and theoretical calculations.HNTs serve as the carrier,which allows CdS to be uniformly dispersed onto its surface as small particles,increasing effective contact with H_(2)O and O_(2) for H_(2)O_(2) formation.Simultaneously,it resulted in the formation of a Schottky junction between NiS and CdS,which not only favors photogenerated charges separating efficiently but also provides a unidirectional path to transfer electrons.Consequently,the optimized NiS/CdS/HNTs composite demonstrates an H_(2)O_(2) evolution rate of 380.5μmol·g^(-1)·h^(-1) without adding any sacrificial agent or extra O_(2),nearly 5.0 times that of pure CdS.This work suggests a feasible idea for designing and developing highly active and low-cost solar energy catalytic composite materials.展开更多
Two-dimensional(2D)heterojunctions are promising photocatalysts for hydrogen production due to their unique ability to efficiently convert solar energy to green fuels.In this work,an S-scheme 2D/2D FTiO_(2)/CdS hetero...Two-dimensional(2D)heterojunctions are promising photocatalysts for hydrogen production due to their unique ability to efficiently convert solar energy to green fuels.In this work,an S-scheme 2D/2D FTiO_(2)/CdS heterostructure was designed and synthesized via a facile hydrothermal method.The hydrogen evolution rate of optimal F-TiO_(2)/CdS photocatalyst irradiated with simulated sunlight reached to 1.7 mmol g^(−1) h^(−1),which was about 7 times that of pristine CdS nanosheets,1.5 times that of TiO_(2) nanoparticles composited with CdS nanosheets,and the apparent quantum efficiency at 420 nm was 4.3%.The insitu Kelvin probe force microscopy results showed that the built-in electric field strength(BIEF)of 2D/2D F-TiO_(2)/CdS is about 6.2×10^(3) V cm^(−1) under the dark condition,which is about 2.3 times that of TiO_(2) nanoparticles composited with CdS nanosheets.Moreover,in-situ electron paramagnetic resonance results showed that the valence band position of F-TiO_(2) is more positive and showed a clear signal peak,suggesting that F-TiO_(2) could generate more hydroxyl radicals.When F-TiO_(2) contacts with CdS,the signals of both radicals are significantly enhanced,indicating that the reducing ability of CdS and the oxidizing ability of F-TiO_(2) are well preserved.These results verify that S-scheme 2D/2D F-TiO_(2)/CdS processes stronger BIEF,which could effectively enhance the photocatalytic hydrogen production activity.展开更多
Efficient photocatalytic water splitting can be significantly enhanced through the careful design of S-scheme heterostructures,which play a pivotal role in optimizing performance.Herein,we report the construction of Z...Efficient photocatalytic water splitting can be significantly enhanced through the careful design of S-scheme heterostructures,which play a pivotal role in optimizing performance.Herein,we report the construction of ZnIn_(2)S_(4)/CdS S-scheme heterojunctions under ambient conditions,based on a sonochemical strategy.This structure is facilitated by the well-matched interface between the(007)plane of layered ZnIn_(2)S_(4)and the(101)plane of CdS,leading to a threshold optical response of 2.12 eV,which optimally aligns with visible light absorption.As a proof of concept,the resulting ZnIn_(2)S_(4)/CdS catalysts demonstrate a remarkable improvement in photocatalytic H_(2) evolution,achieving a rate of 5678.2μmol h^(-1)g^(-1)under visible light irradiation(λ>400 nm).This rate is approximately 10 times higher than that of pristine ZnIn_(2)S_(4)nanosheets(NSs)and about 4.6 times higher than that of CdS nanoparticles(NPs),surpassing the performance of most ZnIn_(2)S_(4)-based photocatalysts reported to date.Moreover,they deliver a robust photocatalytic performance during long-term operation of up to 60 h,showing their potential for use in practical applications.Based on the theoretical calculation and experimental results,it is verified that the movements of electrons and holes in the opposite direction could be induced by the disparity in the work function and the internal electric field within the interfaces,thus facilitating the construction of S-scheme heterojunctions,which fundamentally suppresses carrier recombination while minimizing photocorrosion of ZnIn_(2)S_(4)toward enhanced photocatalytic behaviors.展开更多
Defects in crystals can have a profound impact on their electronic structure and physicochemical proper-ties.To address the limitations in photogenerated carrier mobility and to suppress the recombination of photogene...Defects in crystals can have a profound impact on their electronic structure and physicochemical proper-ties.To address the limitations in photogenerated carrier mobility and to suppress the recombination of photogenerated electrons and holes,defect engineering has been employed in the design of photocata-lysts.By creating appropriate defect energy levels or trap states,can be introduced into the photocatalyst.This modification alters the migration paths of photogenerated carriers,facilitating the rapid transfer of photogenerated charges to the catalyst surface for redox reactions.However,as a typical transition metal photocatalyst,cadmium sulfide(CdS)faces challenges related to photocorrosion,with poor photostability being a significant barrier to its large-scale production and utilization.In this study,we focus on three-dimensional CdS and CeO_(2) hollow spheres,regulating the vacancy contents in CdS and CeO_(2) under the guidance of a defect design strategy.This approach aims to construct a hollow core-shell heterojunction of H-CeO_(2)/H-CdS containing both sulfur and oxygen dual defects,thereby enhancing the photocatalytic activity and photostability of CdS-based composite materials.By employing a well-considered defect de-sign,the electronic structure of the catalyst can be modulated,extending the light absorption range into the visible-near-infrared region.Additionally,density functional theory(DFT)calculations were conducted to analyze the influence of sulfur and oxygen defects on the enhanced photocatalytic activity of the het-erojunction.The mechanism of the photocatalytic hydrogen evolution reaction with the heterojunction is summarized,providing insights into the improved performance of the material.展开更多
文摘The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS QDs and hollow nanotube In_(2)O_(3)is successfully achieved using an electrostatic self-assembly method.Under visible light irradiation,all CdS-In_(2)O_(3)composites exhibit higher hydrogen evolution efficiency compared to pure CdS QDs.Notably,the photocatalytic H_(2)evolution rate of the optimal CdS-7%In_(2)O_(3)composite is determined to be 2258.59μmol g^(−1)h^(−1),approximately 12.3 times higher than that of pure CdS.The cyclic test indicates that the CdS-In_(2)O_(3)composite maintains considerable activity even after 5 cycles,indicating its excellent stability.In situ X-ray photoelectron spectroscopy and density functional theory calculations confirm that carrier migration in CdS-In_(2)O_(3)composites adheres to a typical S-scheme heterojunction mechanism.Additionally,a series of characterizations demonstrate that the formation of S-scheme heterojunctions between In_(2)O_(3)and CdS inhibits charge recombination and accelerates the separation and migration of photogenerated carriers in the CdS QDs,thus achieving enhanced photocatalytic performance.This work elucidates the pivotal role of S-scheme heterojunctions in photocatalytic H_(2)production and offers novel insights into the construction of effective composite photocatalysts.
文摘Hydrogen peroxide(H_(2)O_(2)),an environmentally friendly chemical with high value,is extensively used in industrial production and daily life.However,the traditional anthraquinone method for H_(2)O_(2) production is associated with a highly energy-consuming and heavily polluting process.Solor-driven photocatalytic evolution of H_(2)O_(2) is a promising,eco-friendly,and energy-efficient strategy that holds great potential to substitute the traditional approach.Here,a ternary photocatalyst,NiS/CdS/Halloysite nanotubes(NiS/CdS/HNTs)is designed and prepared with an earth-abundant clay mineral HNTs as the support and NiS as a co-catalyst.The pivotal roles of HNTs and NiS in the photocatalytic process are elucidated by experiments and theoretical calculations.HNTs serve as the carrier,which allows CdS to be uniformly dispersed onto its surface as small particles,increasing effective contact with H_(2)O and O_(2) for H_(2)O_(2) formation.Simultaneously,it resulted in the formation of a Schottky junction between NiS and CdS,which not only favors photogenerated charges separating efficiently but also provides a unidirectional path to transfer electrons.Consequently,the optimized NiS/CdS/HNTs composite demonstrates an H_(2)O_(2) evolution rate of 380.5μmol·g^(-1)·h^(-1) without adding any sacrificial agent or extra O_(2),nearly 5.0 times that of pure CdS.This work suggests a feasible idea for designing and developing highly active and low-cost solar energy catalytic composite materials.
基金supported by the National Natural Science Foundation of China(No.22378372).
文摘Two-dimensional(2D)heterojunctions are promising photocatalysts for hydrogen production due to their unique ability to efficiently convert solar energy to green fuels.In this work,an S-scheme 2D/2D FTiO_(2)/CdS heterostructure was designed and synthesized via a facile hydrothermal method.The hydrogen evolution rate of optimal F-TiO_(2)/CdS photocatalyst irradiated with simulated sunlight reached to 1.7 mmol g^(−1) h^(−1),which was about 7 times that of pristine CdS nanosheets,1.5 times that of TiO_(2) nanoparticles composited with CdS nanosheets,and the apparent quantum efficiency at 420 nm was 4.3%.The insitu Kelvin probe force microscopy results showed that the built-in electric field strength(BIEF)of 2D/2D F-TiO_(2)/CdS is about 6.2×10^(3) V cm^(−1) under the dark condition,which is about 2.3 times that of TiO_(2) nanoparticles composited with CdS nanosheets.Moreover,in-situ electron paramagnetic resonance results showed that the valence band position of F-TiO_(2) is more positive and showed a clear signal peak,suggesting that F-TiO_(2) could generate more hydroxyl radicals.When F-TiO_(2) contacts with CdS,the signals of both radicals are significantly enhanced,indicating that the reducing ability of CdS and the oxidizing ability of F-TiO_(2) are well preserved.These results verify that S-scheme 2D/2D F-TiO_(2)/CdS processes stronger BIEF,which could effectively enhance the photocatalytic hydrogen production activity.
基金supported by the National Natural Science Foundation of China(NSFC,Grant No.52372063,62204246 and 52401244)the Young Elite Scientists Sponsorship Program by CAST(Grant No.2023QNRC001)+1 种基金the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20233001,GZC20233006)the China Postdoctoral Science Foundation(Grant No.2024M753526)。
文摘Efficient photocatalytic water splitting can be significantly enhanced through the careful design of S-scheme heterostructures,which play a pivotal role in optimizing performance.Herein,we report the construction of ZnIn_(2)S_(4)/CdS S-scheme heterojunctions under ambient conditions,based on a sonochemical strategy.This structure is facilitated by the well-matched interface between the(007)plane of layered ZnIn_(2)S_(4)and the(101)plane of CdS,leading to a threshold optical response of 2.12 eV,which optimally aligns with visible light absorption.As a proof of concept,the resulting ZnIn_(2)S_(4)/CdS catalysts demonstrate a remarkable improvement in photocatalytic H_(2) evolution,achieving a rate of 5678.2μmol h^(-1)g^(-1)under visible light irradiation(λ>400 nm).This rate is approximately 10 times higher than that of pristine ZnIn_(2)S_(4)nanosheets(NSs)and about 4.6 times higher than that of CdS nanoparticles(NPs),surpassing the performance of most ZnIn_(2)S_(4)-based photocatalysts reported to date.Moreover,they deliver a robust photocatalytic performance during long-term operation of up to 60 h,showing their potential for use in practical applications.Based on the theoretical calculation and experimental results,it is verified that the movements of electrons and holes in the opposite direction could be induced by the disparity in the work function and the internal electric field within the interfaces,thus facilitating the construction of S-scheme heterojunctions,which fundamentally suppresses carrier recombination while minimizing photocorrosion of ZnIn_(2)S_(4)toward enhanced photocatalytic behaviors.
基金financially supported by the National Natural Science Foundation of China(Nos.21871065 and 22071038)the Heilongjiang Touyan Team(No.HITTY-20190033)+1 种基金the Interdisci-plinary Research Foundation of HIT(No.IR2021205)the China Postdoctoral Foundation(No.GZC20241809).
文摘Defects in crystals can have a profound impact on their electronic structure and physicochemical proper-ties.To address the limitations in photogenerated carrier mobility and to suppress the recombination of photogenerated electrons and holes,defect engineering has been employed in the design of photocata-lysts.By creating appropriate defect energy levels or trap states,can be introduced into the photocatalyst.This modification alters the migration paths of photogenerated carriers,facilitating the rapid transfer of photogenerated charges to the catalyst surface for redox reactions.However,as a typical transition metal photocatalyst,cadmium sulfide(CdS)faces challenges related to photocorrosion,with poor photostability being a significant barrier to its large-scale production and utilization.In this study,we focus on three-dimensional CdS and CeO_(2) hollow spheres,regulating the vacancy contents in CdS and CeO_(2) under the guidance of a defect design strategy.This approach aims to construct a hollow core-shell heterojunction of H-CeO_(2)/H-CdS containing both sulfur and oxygen dual defects,thereby enhancing the photocatalytic activity and photostability of CdS-based composite materials.By employing a well-considered defect de-sign,the electronic structure of the catalyst can be modulated,extending the light absorption range into the visible-near-infrared region.Additionally,density functional theory(DFT)calculations were conducted to analyze the influence of sulfur and oxygen defects on the enhanced photocatalytic activity of the het-erojunction.The mechanism of the photocatalytic hydrogen evolution reaction with the heterojunction is summarized,providing insights into the improved performance of the material.
