Engineering the specific active sites of photocatalysts for simultaneously promoting CO_(2)and H_(2)O activation is important to achieve the efficient conversion of CO_(2)to hydrocarbon with H_(2)O as a proton source ...Engineering the specific active sites of photocatalysts for simultaneously promoting CO_(2)and H_(2)O activation is important to achieve the efficient conversion of CO_(2)to hydrocarbon with H_(2)O as a proton source under sunlight.Herein,we delicately design the In/TiO_(2)-VOphotocatalyst by engineering In single atoms(SAs)and oxygen vacancies(VOs)on porous TiO_(2).The relation between structure and performance of the photocatalyst is clarified by both experimental and theoretical analyses at the atomic levels.The In/TiO_(2)-VOphotocatalyst furnish a high CH_(4)production rate up to 35.49μmol g^(-1)h^(-1)with a high selectivity of 91.3%under simulated sunlight,while only CO is sluggishly generated on TiO_(2)-VO.The combination of in situ spectroscopic analyses with theoretical calculations reveal that the VOsites accelerate H_(2)O dissociation and increase proton feeding for CO_(2)reduction.Furthermore,the VOregulated In-Ti dual sites enable the formation of a stable adsorption conformation of In-C-O-Ti intermediate,which is responsible for the highly selective reduction of CO_(2)to CH_(4).This work demonstrates a new strategy for the development of effective photocatalysts by coupling metal SA sites with the adjacent metal sites of support to synergistically enhance the activity and selectivity of CO_(2)photoreduction.展开更多
Constructing a core-shell nanostructured photocatalyst by integration of plasmonic metal nanocrystals and a semiconductor can offer large active metal/semiconductor interfacial areas and avoid aggregation of the metal...Constructing a core-shell nanostructured photocatalyst by integration of plasmonic metal nanocrystals and a semiconductor can offer large active metal/semiconductor interfacial areas and avoid aggregation of the metal nanocrystals.Herein,well-defined Au@ZnO core-shell nanostructures were prepared by coating ZnO on cetyltrimethylammonium bromide(CTAB)stabilized Au nanospheres in aqueous solution.The resultant core-shell nanostructures have Au-nanosphere cores with a diameter of~55 nm and ZnO shells with a thickness of~50 nm.After calcination at 350℃in air,the mesoporous ZnO shell with higher crystallinity and a larger surface area was obtained without any significant change in the morphology or plasmon band of Au@ZnO.The specific surface plasmon resonance of the Au-nanosphere cores endows the Au@ZnO nanostructures with strong visible light absorption around 550 nm.The photocatalytic degradation of an organic pollutant was performed under simulated sunlight and monochromatic LED light with three different wavelengths(365 nm,520 nm,660 nm),demonstrating the enhanced photocatalysis of the Au@ZnO nanostructures.Furthermore,the Au@ZnO as a photoelectrode material presents a higher photocurrent density than that of pure ZnO nanoparticles under simulated sunlight.The electrochemical impedance spectra(EIS)Nyquist plots also confirm the higher charge transfer efficiency of the Au@ZnO nanostructures.Such plasmonic metal-semiconductor core-shell nanostructures would provide a desirable platform for studying plasmon-induced/enhanced processes and have great potential in light-harvesting applications.展开更多
In this work,a new design of ternary core-shell nanostructures of Au@ZnO-Pd was demonstrated to realize the synergetic utilization of a plasmonic effect and an electron-trapping co-catalyst for enhanced photocatalytic...In this work,a new design of ternary core-shell nanostructures of Au@ZnO-Pd was demonstrated to realize the synergetic utilization of a plasmonic effect and an electron-trapping co-catalyst for enhanced photocatalytic performance.In the ternary hybrid nanostructures,ZnO provides photo-generated carriers with higher redox ability,under UV-visible light,and Au nanocrystals perform the plasmonic hot electron injection as well as the local electromagnetic field enhancement of ZnO photoexcitation.Meanwhile,the Pd NPs can efficiently trap the generated electrons to govern the directional separation of the charge carriers.The efficient charge carrier separation in the ternary hybrid nanostructures was confirmed by steady-state PL spectra,time-resolved PL decay spectra,and transient photocurrent responses.The photocatalytic activity of the Au@ZnO-Pd nanostructures was evaluated by photodegrading phenol and methylene blue,respectively,under simulated sunlight(λ=360-780 nm),and the results showed that the Au@ZnO-Pd nanostructures gained a great enhancement of photocatalysis compared with ZnO,ZnO-Pd and Au@ZnO.Moreover,the effect of Pd loading content in the Au@ZnO-Pd nanostructures on the photocatalytic efficiency was studied within a certain range,indicating that the Au@ZnO-Pd photocatalyst with ~1.8 wt%Pd loading exhibited the best photocatalytic activities for photodegrading both phenol and methylene blue.The generation and effect of active species in the photocatalytic process were investigated using ESR testing and radical scavenging experiments.As a consequence,the integration of the ternary Au@ZnO-Pd core-shell nanostructures could achieve collective effects to greatly increase the photocatalytic efficiency.展开更多
Exploring efficient photocatalysts for solar driven CO_(2) reduction with water(H_(2)O)as a proton donor is highly imperative but remains a great challenge because the synchronous enhancement of CO_(2) activation,H_(2...Exploring efficient photocatalysts for solar driven CO_(2) reduction with water(H_(2)O)as a proton donor is highly imperative but remains a great challenge because the synchronous enhancement of CO_(2) activation,H_(2)O dissociation and proton transfer is hardly achieved on a photocatalyst.Particularly,the sluggish H_(2)O dissociation impedes the photocatalytic CO_(2) reduction reaction involving multiple proton–electron coupling transfer processes.Herein,a sulfur-doped BiOCl(S-BiOCl)photocatalyst with abundant oxygen vacancies(OV)is developed,which exhibits broadband-light harvesting across solar spectrum and distinct photothermal effect due to photochromism.For photocatalytic CO_(2) reduction with H_(2)O in a gas–solid system,the high CO yield of 49.76μmol·g_(cat)^(-1)·h^(-1) with 100%selectivity is achieved over the S-BiOCl catalyst under a simulated sunlight.The H_(2)O-assisted CO_(2) reduction reaction on S-BiOCl catalyst is triggered by photocatalysis and the photothermal heating further enhances the reaction rate.The kinetic isotope experiments indicate that the sluggish H_(2)O dissociation affects the whole photocatalytic CO_(2) reduction process.The presence of oxygen vacancies promotes the adsorption and activation of H_(2)O and CO_(2),and the doped S sites play a crucial role in boosting H_(2)O dissociation and accelerating the dynamic migration of hydrogen species.As a result,the ingenious integration of OV defects,S sites and photothermal effect in S-BiOCl catalyst conjointly contributes to the significant improvement in photocatalytic CO_(2) reduction performance.展开更多
基金financially supported by the Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(Grant No.LZY23B030006)the Natural Science Foundation of Zhejiang Province of China(LY19B010005)the Fundamental Research Funds of Zhejiang Sci-Tech University(2020Y003)。
文摘Engineering the specific active sites of photocatalysts for simultaneously promoting CO_(2)and H_(2)O activation is important to achieve the efficient conversion of CO_(2)to hydrocarbon with H_(2)O as a proton source under sunlight.Herein,we delicately design the In/TiO_(2)-VOphotocatalyst by engineering In single atoms(SAs)and oxygen vacancies(VOs)on porous TiO_(2).The relation between structure and performance of the photocatalyst is clarified by both experimental and theoretical analyses at the atomic levels.The In/TiO_(2)-VOphotocatalyst furnish a high CH_(4)production rate up to 35.49μmol g^(-1)h^(-1)with a high selectivity of 91.3%under simulated sunlight,while only CO is sluggishly generated on TiO_(2)-VO.The combination of in situ spectroscopic analyses with theoretical calculations reveal that the VOsites accelerate H_(2)O dissociation and increase proton feeding for CO_(2)reduction.Furthermore,the VOregulated In-Ti dual sites enable the formation of a stable adsorption conformation of In-C-O-Ti intermediate,which is responsible for the highly selective reduction of CO_(2)to CH_(4).This work demonstrates a new strategy for the development of effective photocatalysts by coupling metal SA sites with the adjacent metal sites of support to synergistically enhance the activity and selectivity of CO_(2)photoreduction.
基金supported by the National Natural Science Foundation of China(21471004)the China Postdoctoral Science Foundation of Special Funding(2015T80644)the Excellent Youth Talents Support Plan in Colleges and Universities of Anhui Province.
文摘Constructing a core-shell nanostructured photocatalyst by integration of plasmonic metal nanocrystals and a semiconductor can offer large active metal/semiconductor interfacial areas and avoid aggregation of the metal nanocrystals.Herein,well-defined Au@ZnO core-shell nanostructures were prepared by coating ZnO on cetyltrimethylammonium bromide(CTAB)stabilized Au nanospheres in aqueous solution.The resultant core-shell nanostructures have Au-nanosphere cores with a diameter of~55 nm and ZnO shells with a thickness of~50 nm.After calcination at 350℃in air,the mesoporous ZnO shell with higher crystallinity and a larger surface area was obtained without any significant change in the morphology or plasmon band of Au@ZnO.The specific surface plasmon resonance of the Au-nanosphere cores endows the Au@ZnO nanostructures with strong visible light absorption around 550 nm.The photocatalytic degradation of an organic pollutant was performed under simulated sunlight and monochromatic LED light with three different wavelengths(365 nm,520 nm,660 nm),demonstrating the enhanced photocatalysis of the Au@ZnO nanostructures.Furthermore,the Au@ZnO as a photoelectrode material presents a higher photocurrent density than that of pure ZnO nanoparticles under simulated sunlight.The electrochemical impedance spectra(EIS)Nyquist plots also confirm the higher charge transfer efficiency of the Au@ZnO nanostructures.Such plasmonic metal-semiconductor core-shell nanostructures would provide a desirable platform for studying plasmon-induced/enhanced processes and have great potential in light-harvesting applications.
基金supported by the National Natural Science Foundation of China(Grant No.21471004)the Science Foundation of Zhejiang Sci-Tech University(Grant No.17062002-Y).
文摘In this work,a new design of ternary core-shell nanostructures of Au@ZnO-Pd was demonstrated to realize the synergetic utilization of a plasmonic effect and an electron-trapping co-catalyst for enhanced photocatalytic performance.In the ternary hybrid nanostructures,ZnO provides photo-generated carriers with higher redox ability,under UV-visible light,and Au nanocrystals perform the plasmonic hot electron injection as well as the local electromagnetic field enhancement of ZnO photoexcitation.Meanwhile,the Pd NPs can efficiently trap the generated electrons to govern the directional separation of the charge carriers.The efficient charge carrier separation in the ternary hybrid nanostructures was confirmed by steady-state PL spectra,time-resolved PL decay spectra,and transient photocurrent responses.The photocatalytic activity of the Au@ZnO-Pd nanostructures was evaluated by photodegrading phenol and methylene blue,respectively,under simulated sunlight(λ=360-780 nm),and the results showed that the Au@ZnO-Pd nanostructures gained a great enhancement of photocatalysis compared with ZnO,ZnO-Pd and Au@ZnO.Moreover,the effect of Pd loading content in the Au@ZnO-Pd nanostructures on the photocatalytic efficiency was studied within a certain range,indicating that the Au@ZnO-Pd photocatalyst with ~1.8 wt%Pd loading exhibited the best photocatalytic activities for photodegrading both phenol and methylene blue.The generation and effect of active species in the photocatalytic process were investigated using ESR testing and radical scavenging experiments.As a consequence,the integration of the ternary Au@ZnO-Pd core-shell nanostructures could achieve collective effects to greatly increase the photocatalytic efficiency.
基金supported by the Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(No.LZY23B030006)the Natural Science Foundation of Zhejiang Province of China(No.LY19B010005)the Fundamental Research Funds of Zhejiang Sci-Tech University(No.2020Y003).
文摘Exploring efficient photocatalysts for solar driven CO_(2) reduction with water(H_(2)O)as a proton donor is highly imperative but remains a great challenge because the synchronous enhancement of CO_(2) activation,H_(2)O dissociation and proton transfer is hardly achieved on a photocatalyst.Particularly,the sluggish H_(2)O dissociation impedes the photocatalytic CO_(2) reduction reaction involving multiple proton–electron coupling transfer processes.Herein,a sulfur-doped BiOCl(S-BiOCl)photocatalyst with abundant oxygen vacancies(OV)is developed,which exhibits broadband-light harvesting across solar spectrum and distinct photothermal effect due to photochromism.For photocatalytic CO_(2) reduction with H_(2)O in a gas–solid system,the high CO yield of 49.76μmol·g_(cat)^(-1)·h^(-1) with 100%selectivity is achieved over the S-BiOCl catalyst under a simulated sunlight.The H_(2)O-assisted CO_(2) reduction reaction on S-BiOCl catalyst is triggered by photocatalysis and the photothermal heating further enhances the reaction rate.The kinetic isotope experiments indicate that the sluggish H_(2)O dissociation affects the whole photocatalytic CO_(2) reduction process.The presence of oxygen vacancies promotes the adsorption and activation of H_(2)O and CO_(2),and the doped S sites play a crucial role in boosting H_(2)O dissociation and accelerating the dynamic migration of hydrogen species.As a result,the ingenious integration of OV defects,S sites and photothermal effect in S-BiOCl catalyst conjointly contributes to the significant improvement in photocatalytic CO_(2) reduction performance.
