Solid non-conjugated polymers have long been regarded as insulators due to deficiency of delocalizedπelectrons along the molecular chain framework.Up to date,origin of insulating polymer regulated charge transfer has...Solid non-conjugated polymers have long been regarded as insulators due to deficiency of delocalizedπelectrons along the molecular chain framework.Up to date,origin of insulating polymer regulated charge transfer has not yet been uncovered.In this work,we unleash the root origin of charge transport capability of insulating polymer in photocatalysis.We ascertain that insulating polymer plays crucial roles in fine tuning of electronic structure of transition metal chalcogenides(TMCs),which mainly include altering surface electron density of TMCs for accelerating charge transport kinetics,triggering the generation of defect over TMCs for prolonging carrier lifetime,and acting as hole-trapping mediator for retarding charge recombination.These synergistic roles contribute to the charge transfer of insulating polymer.Our work opens a new vista of utilizing solid insulating polymers for maneuvering charge transfer toward solar energy conversion.展开更多
A novel WO3-x/TiO2 film as photoanode was synthesized for photoelectrocatalytic（PEC） reduction of CO2 into formic acid（HCOOH）. The films prepared by doctor blade method were characterized with X-ray diffractometer...A novel WO3-x/TiO2 film as photoanode was synthesized for photoelectrocatalytic（PEC） reduction of CO2 into formic acid（HCOOH）. The films prepared by doctor blade method were characterized with X-ray diffractometer（XRD）, scanning electron microscope（SEM） and transmission electron microscope（TEM）. The existence of oxygen vacancies in the WO3-x was confirmed with an X-ray photoelectron spectroscopy（XPS）, and the accurate oxygen index was determined by a modified potentiometric titrimetry method. After 3h of photoelectrocatalytic reduction, the formic acid yield of the WO3-x/TiO2 film is 872 nmol/cm^2, which is 1.83 times that of the WO3/TiO2 film. The results of PEC performance demonstrate that the introduction of WO3-x nanoparticles can improve the charge transfer performance so as to enhance the performance of PEC reduction of CO2 into formic acid.展开更多
The conversion of CO2 and water to value-added chemicals under sunlight irradiation, especially by photoelectrocatalytic reduction process, is always a dream for human beings. A new artificial photosynthesis system co...The conversion of CO2 and water to value-added chemicals under sunlight irradiation, especially by photoelectrocatalytic reduction process, is always a dream for human beings. A new artificial photosynthesis system composed of a metalloporphyrin-functionalized TiO2 photocathode and BiVO4 photoanode can efficiently transform CO2 and water to methanol, which is accompanied by oxygen release. This photoelectrocatalytic system smoothly produces methanol at a rate of 55.5 μM h^–1 cm^– 2, with 0.6 V being the membrane voltage in plants. The production of hydrogen can also be observed when the voltage is more than 0.75 V, due to photocatalysis. Our results evidently indicate that the molecules of metalloporphyrin attached onto the surface of anatase (TiO2) behave as chlorophyll, NADP, and Calvin cycle in plant cells.展开更多
A possible mechanism for boosting the visible-light photoactivities of graphitic carbon nitride(g-C3N4)nanosheets for CO2 reduction via coupling with the electron donor Co-metal-organic framework(MOF)is proposed in th...A possible mechanism for boosting the visible-light photoactivities of graphitic carbon nitride(g-C3N4)nanosheets for CO2 reduction via coupling with the electron donor Co-metal-organic framework(MOF)is proposed in this study.Specifically,Co-MOF as an electron donor is capable of transferring the photogenerated electrons in the lowest unoccupied molecular orbital(LUMO)to the conduction band of g-C3N4 to facilitate charge separation.As expected,the prepared Co-MOF/g-C3N4 nanocomposites display excellent visible-light-driven photocatalytic CO2 reduction activities.The CO production rate of 6.75μmol g–1 h–1 and CH4 evolution rate of 5.47μmol g–1 h–1 are obtained,which are approximately 2 times those obtained with the original g-C3N4 under the same conditions.Based on a series of analyses,it is shown that the introduction of Co-MOF not only broadens the range of visible-light absorption but also enhances the charge separation,which improves the photocatalytic activity of g-C3N4 to a higher level.In particular,the hydroxyl radical(·OH)experiment was operated under 590 nm(single-wavelength)irradiation,which further proved that the photogenerated electrons in the LUMO of Co-MOF can successfully migrate to g-C3N4.This work may provide an important strategy for the design of highly efficient g-C3N4-based photocatalysts for CO2 reduction.展开更多
The active site amount of photocatalysts,being the key factors in photocatalytic reactions,directly affects the photocatalytic performance of the photocatalyst.Pristine graphitic carbon nitride(g‐C_(3)N_(4))exhibits ...The active site amount of photocatalysts,being the key factors in photocatalytic reactions,directly affects the photocatalytic performance of the photocatalyst.Pristine graphitic carbon nitride(g‐C_(3)N_(4))exhibits moderate photocatalytic activity due to insufficient active sites.In this study,cyano‐modified porous g‐C_(3)N_(4)nanosheets(MCN‐0.5)were synthesized through molecular self‐assembly and alkali‐assisted strategies.The cyano group acted as the active site of the photocatalytic reaction,because the good electron‐withdrawing property of the cyano group promoted carrier separation.Benefiting from the effect of the active sites,MCN‐0.5 exhibited significantly enhanced photocatalytic activity for CO2 reduction under visible light irradiation.Notably,the photocatalytic activity of MCN‐0.5 was significantly reduced when the cyano groups were removed by hydrochloric acid(HCl)treatment,further verifying the role of cyano groups as active sites.The photoreduction of Pt nanoparticles provided an intuitive indication that the introduction of cyano groups provided more active sites for the photocatalytic reaction.Furthermore,the controlled experiments showed that g‐C_(3)N_(4)grafted with cyano groups using melamine as the precursor exhibited enhanced photocatalytic activity,which proved the versatility of the strategy for enhancing the activity of g‐C_(3)N_(4)via cyano group modification.In situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations were used to investigate the mechanism of enhanced photocatalytic activity for CO2 reduction by cyano‐modified g‐C_(3)N_(4).This work provides a promising route for promoting efficient solar energy conversion by designing active sites in photocatalysts.展开更多
Although CO_(2)photoreduction is a promising method for solar‐to‐fuel conversion,it suffers from low charge transfer efficiency of the photocatalysts.To improve the CO_(2)photoreduction performance,introduction of e...Although CO_(2)photoreduction is a promising method for solar‐to‐fuel conversion,it suffers from low charge transfer efficiency of the photocatalysts.To improve the CO_(2)photoreduction performance,introduction of electron‐accumulated materials on the photocatalyst surface is considered an effective method.In this study,the Bi_(19)S_(27)Br_(3)/BiOBr composites were designed and synthesized.The Bi19S27Br3 nanorod in this photocatalytic system acts as an electron‐accumulated active site for extracting the photogenerated electrons on the BiOBr surface and for effectively activating the CO2 molecules.As a result,Bi_(19)S_(27)Br_(3)/BiOBr composites exhibit the higher charge carrier transfer efficiency and further improves the CO_(2)photoreduction performance relative to that of pure Bi_(19)S_(27)Br_(3)and BiOBr.The rate of CO formation using Bi_(19)S_(27)Br_(3)/BiOBr‐5 is about 8.74 and 2.40 times that using Bi_(19)S_(27)Br_(3)and BiOBr,respectively.This work provides new insights for the application of Bi_(19)S_(27)Br_(3)as an electron‐accumulating site for achieving high photocatalytic CO2 reduction performance in the future.展开更多
Type‐II‐heterojunction TiO2nanorod arrays(NAs)are achieved by a combination of reduced and pristine TiO2NAs through a simple electrochemical reduction.The heterojunction‐structured TiO2NAs exhibit an enhanced photo...Type‐II‐heterojunction TiO2nanorod arrays(NAs)are achieved by a combination of reduced and pristine TiO2NAs through a simple electrochemical reduction.The heterojunction‐structured TiO2NAs exhibit an enhanced photo‐efficiency,with respect to those of pristine TiO2NAs and completely reduced black TiO2.The improved efficiency can be attributed to a synergistic effect of two contributions of the partially reduced TiO2NAs.The light absorption is significantly increased,from theUV to the visible spectrum.Moreover,the type II structure leads to enhanced separation and transport of the electrons and charges.The proposed electrochemical approach could be applied to various semiconductors for a control of the band structure and improved photoelectrochemical performance.展开更多
Dynamic defects on halide perovskite materials,caused by ion dissociation and migration under light illumination,typically result in undesirable energy dissipation and limited energy conversion efficiency.However,in t...Dynamic defects on halide perovskite materials,caused by ion dissociation and migration under light illumination,typically result in undesirable energy dissipation and limited energy conversion efficiency.However,in this work,we demonstrated that dynamic halogen defects generated by the same process in bismuth oxyhalide(Bi_(5)O_(7)Cl)materials can act as active sites to promote charge separation and photocatalytic efficiency.Mechanistic studies and density functional theory calculations revealed that dynamic Cl defects affected the electronic structure of Bi_(5)O_(7)Cl and photocatalytic CO_(2)reduction process.As active sites,these defects promoted charge transfer,leading to the activation of adsorbed CO_(2)molecules and reduction of the energy barrier of the rate-determining step.Thus,CO_(2)was spontaneously converted into COOH−intermediate and finally reduced to CO with a high efficiency of 108.60μmol g^(−1) and selectivity of 100%after 4-h of CO_(2)photoreduction.This work is highly instructive and valuable to the exploration of dynamic defects on halide-containing materials applied in solar energy conversion.展开更多
Photocatalytic CO2 reduction is thought to be a promising strategy in mitigating the energy crisis and several other environmental problems.Hence,modifying or developing suitable semiconductors with high efficiency of...Photocatalytic CO2 reduction is thought to be a promising strategy in mitigating the energy crisis and several other environmental problems.Hence,modifying or developing suitable semiconductors with high efficiency of photocatalytic CO2 reduction property has become a topic of interest to scientists.In this study,a series of Mo-modified Cs0.33WO3 tungsten bronze were prepared using a"watercontrollable releasing"solvothermal method to produce effective photocatalytic CO2 reduction performance.Interestingly,Mo atoms replaced W partially within the hexagonal crystal structure,leading to a significant increase in photocatalytic CO2 reduction activity of Cs0.33WO3.The 5%Modoped compound displayed the best performance,with the production yield rates of 7.5μmol g^-1h^-1 for CO and3.0μmol g^-1h^-1 for CH3OH under low concentration of CO2 under anaerobic conditions,which is greatly higher than those of pure Cs0.33WO3(3.2μmol g^-1h^-1 for CO and 1.2μmol g^-1h^-1 for CH3OH)and Mo-doped W18O49(1.5μmol g^-1h^-1for CO and 0μmol g^-1h^-1 for CH3OH).More importantly,the as-prepared Mo-doped Cs0.33WO3 series could also induce the photocatalytic reduction of CO2 directly from the air in the presence of oxygen,which is beneficial for practical applications.The superior photocatalytic performance of Mo-doped Cs0.33WO3 series over the popular reduced WO3 may be due to the increase in light absorption induced by the localized surface plasmon resonance(LSPR)effect of Mo5+,large improved charge separation ability,and the co-effect of Mo and Cs in crystal.This study provides a simple strategy for designing highly efficient photocatalysts in low concentration of CO2 reduction.展开更多
Two-dimensional porous nanosheet heterostructure materials,which combine the advantages of both architecture and components,are expected to feature a significant photocatalytic performance toward CO_(2) conversion int...Two-dimensional porous nanosheet heterostructure materials,which combine the advantages of both architecture and components,are expected to feature a significant photocatalytic performance toward CO_(2) conversion into useful fuels.Herein,we provide a facile strategy for fabricating sulfur-doped C_(3)N_(4) porous nanosheets with embedded SnO_(2)-SnS_(2) nanojunctions(S-C_(3)N_(4)/SnO_(2)-SnS_(2))via liquid impregnation-pyrolysis and subsequent sulfidation treatment using a layered supramolecular structure as the precursor of C_(3)N_(4).A hexagonal layered supramolecular structure was first prepared as the precursor of C_(3)N_(4).Then Sn^(4+) ions were intercalated into the supramolecular interlayers through the liquid impregnation method.The subsequent annealing treatment in air simultaneously realized the fabrication and efficient exfoliation of layered C_(3)N_(4) porous nanosheets.Moreover,SnO_(2) nanoparticles were formed and embedded in situ in the porous C_(3)N_(4) nanosheets.In the following sulfidation process under a nitrogen atmosphere,sulfur powder can react with SnO_(2) nanoparticles to form SnO_(2)-SnS_(2) nanojunctions.As expected,the exfoliation of sulfur-doped C_(3)N_(4) porous nanosheets and ternary heterostructure construction could be simultaneously achieved in this work.Sulfur-doped C_(3)N_(4) porous nanosheets with embedded SnO_(2)-SnS_(2) nanojunctions featured abundant active sites,enhanced visible light absorption,and efficient interfacial charge transfer.As expected,the optimized S-C_(3)N_(4)/SnO_(2)-SnS_(2) achieved a much higher gas-phase photocatalytic CO_(2) reduction performance with high yields of CO(21.68μmol g^(−1)h^(−1))and CH_(4)(22.09μmol g^(−1)h^(−1))compared with the control C_(3)N_(4),C_(3)N_(4)/SnO_(2),and S-C_(3)N_(4)/SnS_(2) photocatalysts.The selectivity of CH_(4) reached 80.30%.Such a promising synthetic strategy can be expected to inspire the design of other robust C_(3)N_(4)-based porous nanosheet heterostructures for a broad range of applications.展开更多
The energy crisis and global warming become severe issues. Solar-driven CO2 reduction provides a promising route to confront the predicaments, which has received much attention. The photoelectrochemical（PEC） process...The energy crisis and global warming become severe issues. Solar-driven CO2 reduction provides a promising route to confront the predicaments, which has received much attention. The photoelectrochemical（PEC） process,which can integrate the merits of both photocatalysis and electrocatalysis, boosts splendid talent for CO2 reduction with high efficiency and excellent selectivity. Recent several decades have witnessed the overwhelming development of PEC CO2 reduction. In this review, we attempt to systematically summarize the recent advanced design for PEC CO2 reduction. On account of basic principles and evaluation parameters, we firstly highlight the subtle construction for photocathodes to enhance the efficiency and selectivity of CO2 reduction, which includes the strategies for improving light utilization, supplying catalytic active sites and steering reaction pathway.Furthermore, diversiform novel PEC setups are also outlined.These exploited setups endow a bright window to surmount the intrinsic disadvantages of photocathode, showing promising potentials for future applications. Finally, we underline the challenges and key factors for the further development of PEC CO2 reduction that would enable more efficient designs for setups and deepen systematic understanding for mechanisms.展开更多
文摘Solid non-conjugated polymers have long been regarded as insulators due to deficiency of delocalizedπelectrons along the molecular chain framework.Up to date,origin of insulating polymer regulated charge transfer has not yet been uncovered.In this work,we unleash the root origin of charge transport capability of insulating polymer in photocatalysis.We ascertain that insulating polymer plays crucial roles in fine tuning of electronic structure of transition metal chalcogenides(TMCs),which mainly include altering surface electron density of TMCs for accelerating charge transport kinetics,triggering the generation of defect over TMCs for prolonging carrier lifetime,and acting as hole-trapping mediator for retarding charge recombination.These synergistic roles contribute to the charge transfer of insulating polymer.Our work opens a new vista of utilizing solid insulating polymers for maneuvering charge transfer toward solar energy conversion.
基金Project(21471054)supported by the National Natural Science Foundation of China
文摘A novel WO3-x/TiO2 film as photoanode was synthesized for photoelectrocatalytic（PEC） reduction of CO2 into formic acid（HCOOH）. The films prepared by doctor blade method were characterized with X-ray diffractometer（XRD）, scanning electron microscope（SEM） and transmission electron microscope（TEM）. The existence of oxygen vacancies in the WO3-x was confirmed with an X-ray photoelectron spectroscopy（XPS）, and the accurate oxygen index was determined by a modified potentiometric titrimetry method. After 3h of photoelectrocatalytic reduction, the formic acid yield of the WO3-x/TiO2 film is 872 nmol/cm^2, which is 1.83 times that of the WO3/TiO2 film. The results of PEC performance demonstrate that the introduction of WO3-x nanoparticles can improve the charge transfer performance so as to enhance the performance of PEC reduction of CO2 into formic acid.
基金funded by the Natural Science Foundation of Gansu Province(17JR5RA212)the State Key Laboratory of Coal Conversion(J19-20-913-1)~~
文摘The conversion of CO2 and water to value-added chemicals under sunlight irradiation, especially by photoelectrocatalytic reduction process, is always a dream for human beings. A new artificial photosynthesis system composed of a metalloporphyrin-functionalized TiO2 photocathode and BiVO4 photoanode can efficiently transform CO2 and water to methanol, which is accompanied by oxygen release. This photoelectrocatalytic system smoothly produces methanol at a rate of 55.5 μM h^–1 cm^– 2, with 0.6 V being the membrane voltage in plants. The production of hydrogen can also be observed when the voltage is more than 0.75 V, due to photocatalysis. Our results evidently indicate that the molecules of metalloporphyrin attached onto the surface of anatase (TiO2) behave as chlorophyll, NADP, and Calvin cycle in plant cells.
基金supported by the National Natural Science Foundation of China(21871079,21501052)the Outstanding Youth Project of Natural Science Foundation of Heilongjiang Province(YQ2019B006)~~
文摘A possible mechanism for boosting the visible-light photoactivities of graphitic carbon nitride(g-C3N4)nanosheets for CO2 reduction via coupling with the electron donor Co-metal-organic framework(MOF)is proposed in this study.Specifically,Co-MOF as an electron donor is capable of transferring the photogenerated electrons in the lowest unoccupied molecular orbital(LUMO)to the conduction band of g-C3N4 to facilitate charge separation.As expected,the prepared Co-MOF/g-C3N4 nanocomposites display excellent visible-light-driven photocatalytic CO2 reduction activities.The CO production rate of 6.75μmol g–1 h–1 and CH4 evolution rate of 5.47μmol g–1 h–1 are obtained,which are approximately 2 times those obtained with the original g-C3N4 under the same conditions.Based on a series of analyses,it is shown that the introduction of Co-MOF not only broadens the range of visible-light absorption but also enhances the charge separation,which improves the photocatalytic activity of g-C3N4 to a higher level.In particular,the hydroxyl radical(·OH)experiment was operated under 590 nm(single-wavelength)irradiation,which further proved that the photogenerated electrons in the LUMO of Co-MOF can successfully migrate to g-C3N4.This work may provide an important strategy for the design of highly efficient g-C3N4-based photocatalysts for CO2 reduction.
文摘The active site amount of photocatalysts,being the key factors in photocatalytic reactions,directly affects the photocatalytic performance of the photocatalyst.Pristine graphitic carbon nitride(g‐C_(3)N_(4))exhibits moderate photocatalytic activity due to insufficient active sites.In this study,cyano‐modified porous g‐C_(3)N_(4)nanosheets(MCN‐0.5)were synthesized through molecular self‐assembly and alkali‐assisted strategies.The cyano group acted as the active site of the photocatalytic reaction,because the good electron‐withdrawing property of the cyano group promoted carrier separation.Benefiting from the effect of the active sites,MCN‐0.5 exhibited significantly enhanced photocatalytic activity for CO2 reduction under visible light irradiation.Notably,the photocatalytic activity of MCN‐0.5 was significantly reduced when the cyano groups were removed by hydrochloric acid(HCl)treatment,further verifying the role of cyano groups as active sites.The photoreduction of Pt nanoparticles provided an intuitive indication that the introduction of cyano groups provided more active sites for the photocatalytic reaction.Furthermore,the controlled experiments showed that g‐C_(3)N_(4)grafted with cyano groups using melamine as the precursor exhibited enhanced photocatalytic activity,which proved the versatility of the strategy for enhancing the activity of g‐C_(3)N_(4)via cyano group modification.In situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations were used to investigate the mechanism of enhanced photocatalytic activity for CO2 reduction by cyano‐modified g‐C_(3)N_(4).This work provides a promising route for promoting efficient solar energy conversion by designing active sites in photocatalysts.
文摘Although CO_(2)photoreduction is a promising method for solar‐to‐fuel conversion,it suffers from low charge transfer efficiency of the photocatalysts.To improve the CO_(2)photoreduction performance,introduction of electron‐accumulated materials on the photocatalyst surface is considered an effective method.In this study,the Bi_(19)S_(27)Br_(3)/BiOBr composites were designed and synthesized.The Bi19S27Br3 nanorod in this photocatalytic system acts as an electron‐accumulated active site for extracting the photogenerated electrons on the BiOBr surface and for effectively activating the CO2 molecules.As a result,Bi_(19)S_(27)Br_(3)/BiOBr composites exhibit the higher charge carrier transfer efficiency and further improves the CO_(2)photoreduction performance relative to that of pure Bi_(19)S_(27)Br_(3)and BiOBr.The rate of CO formation using Bi_(19)S_(27)Br_(3)/BiOBr‐5 is about 8.74 and 2.40 times that using Bi_(19)S_(27)Br_(3)and BiOBr,respectively.This work provides new insights for the application of Bi_(19)S_(27)Br_(3)as an electron‐accumulating site for achieving high photocatalytic CO2 reduction performance in the future.
基金supported from the National Natural Science Foundation of China (21425309, 21761132002, 21703040)China Postdoctoral Science Foundation (2017M622051) the 111 Project~~
文摘Type‐II‐heterojunction TiO2nanorod arrays(NAs)are achieved by a combination of reduced and pristine TiO2NAs through a simple electrochemical reduction.The heterojunction‐structured TiO2NAs exhibit an enhanced photo‐efficiency,with respect to those of pristine TiO2NAs and completely reduced black TiO2.The improved efficiency can be attributed to a synergistic effect of two contributions of the partially reduced TiO2NAs.The light absorption is significantly increased,from theUV to the visible spectrum.Moreover,the type II structure leads to enhanced separation and transport of the electrons and charges.The proposed electrochemical approach could be applied to various semiconductors for a control of the band structure and improved photoelectrochemical performance.
基金supported by the National Natural Science Foundation of China(21822601,22176029)Excellent Youth Foundation of Sichuan Scientific Committee(2021JDJQ0006)+1 种基金Fundamental Research Funds for the Central Universities(ZYGX2019Z021)111 Project(B20030)。
文摘Dynamic defects on halide perovskite materials,caused by ion dissociation and migration under light illumination,typically result in undesirable energy dissipation and limited energy conversion efficiency.However,in this work,we demonstrated that dynamic halogen defects generated by the same process in bismuth oxyhalide(Bi_(5)O_(7)Cl)materials can act as active sites to promote charge separation and photocatalytic efficiency.Mechanistic studies and density functional theory calculations revealed that dynamic Cl defects affected the electronic structure of Bi_(5)O_(7)Cl and photocatalytic CO_(2)reduction process.As active sites,these defects promoted charge transfer,leading to the activation of adsorbed CO_(2)molecules and reduction of the energy barrier of the rate-determining step.Thus,CO_(2)was spontaneously converted into COOH−intermediate and finally reduced to CO with a high efficiency of 108.60μmol g^(−1) and selectivity of 100%after 4-h of CO_(2)photoreduction.This work is highly instructive and valuable to the exploration of dynamic defects on halide-containing materials applied in solar energy conversion.
基金supported by the National Natural Science Foundation of China(21975193 and 51602237)the Fundamental Research Funds for the Central Universities(195208011)。
文摘Photocatalytic CO2 reduction is thought to be a promising strategy in mitigating the energy crisis and several other environmental problems.Hence,modifying or developing suitable semiconductors with high efficiency of photocatalytic CO2 reduction property has become a topic of interest to scientists.In this study,a series of Mo-modified Cs0.33WO3 tungsten bronze were prepared using a"watercontrollable releasing"solvothermal method to produce effective photocatalytic CO2 reduction performance.Interestingly,Mo atoms replaced W partially within the hexagonal crystal structure,leading to a significant increase in photocatalytic CO2 reduction activity of Cs0.33WO3.The 5%Modoped compound displayed the best performance,with the production yield rates of 7.5μmol g^-1h^-1 for CO and3.0μmol g^-1h^-1 for CH3OH under low concentration of CO2 under anaerobic conditions,which is greatly higher than those of pure Cs0.33WO3(3.2μmol g^-1h^-1 for CO and 1.2μmol g^-1h^-1 for CH3OH)and Mo-doped W18O49(1.5μmol g^-1h^-1for CO and 0μmol g^-1h^-1 for CH3OH).More importantly,the as-prepared Mo-doped Cs0.33WO3 series could also induce the photocatalytic reduction of CO2 directly from the air in the presence of oxygen,which is beneficial for practical applications.The superior photocatalytic performance of Mo-doped Cs0.33WO3 series over the popular reduced WO3 may be due to the increase in light absorption induced by the localized surface plasmon resonance(LSPR)effect of Mo5+,large improved charge separation ability,and the co-effect of Mo and Cs in crystal.This study provides a simple strategy for designing highly efficient photocatalysts in low concentration of CO2 reduction.
基金supported by the National Natural Science Foundation of China(22072037 and 51772079)the Natural Science Foundation of Heilongjiang Province of China(LH2020B018)。
文摘Two-dimensional porous nanosheet heterostructure materials,which combine the advantages of both architecture and components,are expected to feature a significant photocatalytic performance toward CO_(2) conversion into useful fuels.Herein,we provide a facile strategy for fabricating sulfur-doped C_(3)N_(4) porous nanosheets with embedded SnO_(2)-SnS_(2) nanojunctions(S-C_(3)N_(4)/SnO_(2)-SnS_(2))via liquid impregnation-pyrolysis and subsequent sulfidation treatment using a layered supramolecular structure as the precursor of C_(3)N_(4).A hexagonal layered supramolecular structure was first prepared as the precursor of C_(3)N_(4).Then Sn^(4+) ions were intercalated into the supramolecular interlayers through the liquid impregnation method.The subsequent annealing treatment in air simultaneously realized the fabrication and efficient exfoliation of layered C_(3)N_(4) porous nanosheets.Moreover,SnO_(2) nanoparticles were formed and embedded in situ in the porous C_(3)N_(4) nanosheets.In the following sulfidation process under a nitrogen atmosphere,sulfur powder can react with SnO_(2) nanoparticles to form SnO_(2)-SnS_(2) nanojunctions.As expected,the exfoliation of sulfur-doped C_(3)N_(4) porous nanosheets and ternary heterostructure construction could be simultaneously achieved in this work.Sulfur-doped C_(3)N_(4) porous nanosheets with embedded SnO_(2)-SnS_(2) nanojunctions featured abundant active sites,enhanced visible light absorption,and efficient interfacial charge transfer.As expected,the optimized S-C_(3)N_(4)/SnO_(2)-SnS_(2) achieved a much higher gas-phase photocatalytic CO_(2) reduction performance with high yields of CO(21.68μmol g^(−1)h^(−1))and CH_(4)(22.09μmol g^(−1)h^(−1))compared with the control C_(3)N_(4),C_(3)N_(4)/SnO_(2),and S-C_(3)N_(4)/SnS_(2) photocatalysts.The selectivity of CH_(4) reached 80.30%.Such a promising synthetic strategy can be expected to inspire the design of other robust C_(3)N_(4)-based porous nanosheet heterostructures for a broad range of applications.
基金financially supported in part by the National Key R&D Program of China (2017YFA0207301)the National Basic Research Program of China (973 Program, 2014CB848900)+5 种基金the National Natural Science Foundation of China (21471141 and U1532135)the CAS Key Research Program of Frontier Sciences (QYZDB-SSW-SLH018)the CAS Interdisciplinary Innovation Team, the Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology (2016FXCX003)the Recruitment Program of Global Experts, the CAS Hundred Talent Program, Anhui Provincial Natural Science Foundation (1708085QB26)China Postdoctoral Science Foundation (BH2060000034)the Fundamental Research Funds for the Central Universities (WK2060190064)
文摘The energy crisis and global warming become severe issues. Solar-driven CO2 reduction provides a promising route to confront the predicaments, which has received much attention. The photoelectrochemical（PEC） process,which can integrate the merits of both photocatalysis and electrocatalysis, boosts splendid talent for CO2 reduction with high efficiency and excellent selectivity. Recent several decades have witnessed the overwhelming development of PEC CO2 reduction. In this review, we attempt to systematically summarize the recent advanced design for PEC CO2 reduction. On account of basic principles and evaluation parameters, we firstly highlight the subtle construction for photocathodes to enhance the efficiency and selectivity of CO2 reduction, which includes the strategies for improving light utilization, supplying catalytic active sites and steering reaction pathway.Furthermore, diversiform novel PEC setups are also outlined.These exploited setups endow a bright window to surmount the intrinsic disadvantages of photocathode, showing promising potentials for future applications. Finally, we underline the challenges and key factors for the further development of PEC CO2 reduction that would enable more efficient designs for setups and deepen systematic understanding for mechanisms.
