Promoting activity while inhibiting hazardous byproduct formation remains a great challenge in oxygenated volatile organic compounds(OVOCs)purification.Here,we found that the low-temperature oxidation of ethyl acetate...Promoting activity while inhibiting hazardous byproduct formation remains a great challenge in oxygenated volatile organic compounds(OVOCs)purification.Here,we found that the low-temperature oxidation of ethyl acetate(EA)and the generation rate of CO2 were enhanced by controlling the initial Ag precursor(ions vs.nanoparticles)to engineer catalysts with distinct active site configurations.The reaction rate and TOFAg of Ag nanoparticles/310MnO2(Ag-NP/310MnO2)are 4.3 and 4.1 times higher,respectively,than those of Ag ions/310MnO2(Ag-IS/310MnO2)at 150℃.And Ag-NP/310MnO2 further shows a 1.9-fold higher CO2 selectivity compared to that of Ag-IS/310MnO2.The adsorption ability of EA is much stronger than that of O2 at Ag site,while the opposite trend is observed at oxygen vacancy.The synergy between Ag site(EA adsorption)and oxygen vacancy(O2 dissociation)in Ag-NP/310MnO2 accelerates O2 activation and subsequent EA oxidation.Moreover,abundant active oxygen species(*O)promote the rate-limiting step of acetic acid decomposition,contributing to superior low-temperature CO2 selectivity.However,due to the fierce competition from EA,limited O2 is adsorbed at Ag site-occupied oxygen vacancy,which is difficult to dissociate especially at low temperature,leading to inferior activity of Ag-IS/310MnO2.This work provides a vital scientific basis for enhancing the low-temperature deep oxidation of OVOCs,showcasing remarkable environmental significance.展开更多
This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi2MoO6/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodep...This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi2MoO6/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodeposition of noble metal silver(Ag)onto the composite structure.The catalytic efficiency of semiconductor photocatalysts is greatly improved by utilizing the localized surface plasmon resonance(LSPR)effect observed in Ag nanoparticles(NPs).Furthermore,the noble metal Ag serves as an intermediary bridge facilitating charge transfer between Bi2MoO6and BiOBr,while the formation of a Schottky barrier effectively inhibits the recombination of photo-generated electron-hole pairs.As a result,the Ag-deposited Bi2MoO6/BiOBr film exhibits superior photocatalytic performance in the reduction of CO2compared to its unmodified counterpart.Our experimental results indicate a non-linear relationship between Ag deposition and the efficiency of photocatalytic CO2reduction to CO,characterized by an initial increase in efficiency followed by a decline.The optimized 1.5%-Ag/Bi2MoO6/BiOBr film demonstrates exceptional photocatalytic activity,attaining a CO production rate of 13.65μmol/(g·h).This research explores the fundamental mechanisms that lead to improved photocatalytic CO2reduction capabilities of the Ag/Bi2MoO6/BiOBr film.Our research offers important perspectives for the thoughtful design and production of highly efficient photocatalysts,which are essential for advancing sustainable energy solutions.展开更多
Ethylene(C2H4)in vehicle exhaust is a highly reactive volatile organic compound(VOC).Its photooxidative reaction with NOx contributes to the formation of O3 and secondary organic aerosols(SOA),the latter being a...Ethylene(C2H4)in vehicle exhaust is a highly reactive volatile organic compound(VOC).Its photooxidative reaction with NOx contributes to the formation of O3 and secondary organic aerosols(SOA),the latter being a key precursor of PM2.5.In this study,a novel MgO-supported Ag-Cu bimetallic catalyst was designed and investigated using density functional theory(DFT).The effects of Ag and Cu loading on the geometric structure,stability,and reactant adsorption characteristics of the catalyst were analyzed,and the catalytic oxidation pathways of C2H4over AgCu-MgO was elucidated.The results indicate that loading Ag significantly enhances the adsorption of C2H4.The incorporation of Cu into Ag-MgO to form a AgCu-MgO bimetallic catalyst(dual atom catalyst,DACS)further improves the oxidative activity toward C2H4.Based on the binding energies of the Ag and Cu bimetallic sites and the adsorption energies of C2H4and O2,three representative configurations were selected for detailed reaction pathway analysis.Among them,Configuration 6 of AgCu-MgO exhibited the highest catalytic oxidation performance.This study provides new atomic-scale insights for the rational design of efficient catalysts targeting olefinic pollutants in automotive emissions and offers valuable guidance for advancing exhaust after-treatment technologies.展开更多
The zinc indium sulfide(ZnIn2S4)semiconductors have garnered significant interest in photocatalysis due to their environmentally friendly characteristics,appropriate bandgap,and high absorption coefficient.Howev...The zinc indium sulfide(ZnIn2S4)semiconductors have garnered significant interest in photocatalysis due to their environmentally friendly characteristics,appropriate bandgap,and high absorption coefficient.However,the exploration of advanced strategies to realize the effective and tailored doping still poses significant challenges in enhancing hydrogen evolution performance.In this work,a mild cation exchange strategy is reported to incorporate Ag cations into flower-like ZnIn2S4 microspheres,enabling the selective replacement of Zn atoms by Ag.Remarkably,the as-fabricated Ag-ZnIn2S4 exhibited exceptional photocatalytic hydrogen production performance,achieving a rate of 8098μmol·g−1·h−1 under visible light irradiation.This is 4 times than that of pristine ZnIn2S4(2002μmol·g−1·h−1),and stands as the highest one among metal-doped-ZnIn2S4 photocatalysts ever reported.Along with the theoretical calculations,it has been confirmed that the enhanced photocatalytic hydrogen generation behavior can primarily be attributed to the synergistic effect with improved light absorption,reduced adsorption energy,increased active sites and optimized charge carrier transfer,induced by the cation exchange with Ag in ZnIn2S4.This work might provide some valuable insights on the design and development of highly efficient visible light driven photocatalysts for water splitting applications.展开更多
摘要Promoting activity while inhibiting hazardous byproduct formation remains a great challenge in oxygenated volatile organic compounds(OVOCs)purification.Here,we found that the low-temperature oxidation of ethyl acetate(EA)and the generation rate of CO2 were enhanced by controlling the initial Ag precursor(ions vs.nanoparticles)to engineer catalysts with distinct active site configurations.The reaction rate and TOFAg of Ag nanoparticles/310MnO2(Ag-NP/310MnO2)are 4.3 and 4.1 times higher,respectively,than those of Ag ions/310MnO2(Ag-IS/310MnO2)at 150℃.And Ag-NP/310MnO2 further shows a 1.9-fold higher CO2 selectivity compared to that of Ag-IS/310MnO2.The adsorption ability of EA is much stronger than that of O2 at Ag site,while the opposite trend is observed at oxygen vacancy.The synergy between Ag site(EA adsorption)and oxygen vacancy(O2 dissociation)in Ag-NP/310MnO2 accelerates O2 activation and subsequent EA oxidation.Moreover,abundant active oxygen species(*O)promote the rate-limiting step of acetic acid decomposition,contributing to superior low-temperature CO2 selectivity.However,due to the fierce competition from EA,limited O2 is adsorbed at Ag site-occupied oxygen vacancy,which is difficult to dissociate especially at low temperature,leading to inferior activity of Ag-IS/310MnO2.This work provides a vital scientific basis for enhancing the low-temperature deep oxidation of OVOCs,showcasing remarkable environmental significance.
基金Supported by the National Natural Science Foundation of China(21978196)Natural Science Foundation of Shanxi Province(201801D211008,202403021211018)+1 种基金Shanxi Provincial Education Department(S202413597023)Jincheng High Efficiency Conversion and Utilization Technology Innovation Center of CO2 Energy and Biomass Energy。
摘要This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi2MoO6/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodeposition of noble metal silver(Ag)onto the composite structure.The catalytic efficiency of semiconductor photocatalysts is greatly improved by utilizing the localized surface plasmon resonance(LSPR)effect observed in Ag nanoparticles(NPs).Furthermore,the noble metal Ag serves as an intermediary bridge facilitating charge transfer between Bi2MoO6and BiOBr,while the formation of a Schottky barrier effectively inhibits the recombination of photo-generated electron-hole pairs.As a result,the Ag-deposited Bi2MoO6/BiOBr film exhibits superior photocatalytic performance in the reduction of CO2compared to its unmodified counterpart.Our experimental results indicate a non-linear relationship between Ag deposition and the efficiency of photocatalytic CO2reduction to CO,characterized by an initial increase in efficiency followed by a decline.The optimized 1.5%-Ag/Bi2MoO6/BiOBr film demonstrates exceptional photocatalytic activity,attaining a CO production rate of 13.65μmol/(g·h).This research explores the fundamental mechanisms that lead to improved photocatalytic CO2reduction capabilities of the Ag/Bi2MoO6/BiOBr film.Our research offers important perspectives for the thoughtful design and production of highly efficient photocatalysts,which are essential for advancing sustainable energy solutions.
基金Supported by the National Natural Science Foundation of China Project(22362018)the Yunnan Fundamental Research Projects(202401AS070102)。
摘要Ethylene(C2H4)in vehicle exhaust is a highly reactive volatile organic compound(VOC).Its photooxidative reaction with NOx contributes to the formation of O3 and secondary organic aerosols(SOA),the latter being a key precursor of PM2.5.In this study,a novel MgO-supported Ag-Cu bimetallic catalyst was designed and investigated using density functional theory(DFT).The effects of Ag and Cu loading on the geometric structure,stability,and reactant adsorption characteristics of the catalyst were analyzed,and the catalytic oxidation pathways of C2H4over AgCu-MgO was elucidated.The results indicate that loading Ag significantly enhances the adsorption of C2H4.The incorporation of Cu into Ag-MgO to form a AgCu-MgO bimetallic catalyst(dual atom catalyst,DACS)further improves the oxidative activity toward C2H4.Based on the binding energies of the Ag and Cu bimetallic sites and the adsorption energies of C2H4and O2,three representative configurations were selected for detailed reaction pathway analysis.Among them,Configuration 6 of AgCu-MgO exhibited the highest catalytic oxidation performance.This study provides new atomic-scale insights for the rational design of efficient catalysts targeting olefinic pollutants in automotive emissions and offers valuable guidance for advancing exhaust after-treatment technologies.
基金supported by the National Natural Science Foundation of China(Nos.52272085 and 52372063)Zhejiang Provincial Natural Science Foundation of China(No.LY23E020002)+1 种基金Ningbo Youth Science and Technology Innovation Leading Talents Project(No.2023QL031)the Postdoctoral Fellowship Program of CPSF(No.GZC20233006).
摘要The zinc indium sulfide(ZnIn2S4)semiconductors have garnered significant interest in photocatalysis due to their environmentally friendly characteristics,appropriate bandgap,and high absorption coefficient.However,the exploration of advanced strategies to realize the effective and tailored doping still poses significant challenges in enhancing hydrogen evolution performance.In this work,a mild cation exchange strategy is reported to incorporate Ag cations into flower-like ZnIn2S4 microspheres,enabling the selective replacement of Zn atoms by Ag.Remarkably,the as-fabricated Ag-ZnIn2S4 exhibited exceptional photocatalytic hydrogen production performance,achieving a rate of 8098μmol·g−1·h−1 under visible light irradiation.This is 4 times than that of pristine ZnIn2S4(2002μmol·g−1·h−1),and stands as the highest one among metal-doped-ZnIn2S4 photocatalysts ever reported.Along with the theoretical calculations,it has been confirmed that the enhanced photocatalytic hydrogen generation behavior can primarily be attributed to the synergistic effect with improved light absorption,reduced adsorption energy,increased active sites and optimized charge carrier transfer,induced by the cation exchange with Ag in ZnIn2S4.This work might provide some valuable insights on the design and development of highly efficient visible light driven photocatalysts for water splitting applications.