The conventional p-n heterojunction photocatalysts suffer from the incompatibility between the interfacial charge transfer efficiency and the redox ability of charge carriers.To optimize the interfacial charge transfe...The conventional p-n heterojunction photocatalysts suffer from the incompatibility between the interfacial charge transfer efficiency and the redox ability of charge carriers.To optimize the interfacial charge transfer of the conventional BiOI/TiO_(2) p-n photocatalyst,we synthesized the BiOI/Bi/TiO_(2) ternary photocatalyst with sandwiched metallic bismuth(Bi~0)by the oxygen-vacancy assisted method.The DFT calculation and structural characterizations confirmed the reaction of the electron-rich oxygen vacancies in the 2D-TiO_(2) nanosheets(TiO_(2)-NS)with the adsorbed BiO~+species.This reaction broke the Bi-O bonds to form Bi^(0) nanoparticles in-situ at the interface but still maintained the p-n heterojunction well.The NO-TPD and XRD analyses for samples correlated the Bi~0 formation with the oxygen vacancy concentrations well.The sandwiched Bi~0 functioned as an electronic transfer mediator like that in the Z-scheme heterostructure.Comparing with 0.20 BiOI/TiO_(2)-NP(NP,Nanoparticles),0.20 BiOI/Bi/TiO_(2)-NS-a(NS,Nanosheet)showed a much improved catalytic performance,i.e.,duplicated apparent quantum yield(AQY)and triplicated reaction rate constant(k).Also,the formation mechanism and the reaction mechanism were investigated in detail.This work provides a new strategy for the improving of the conventional p-n photocatalysts and new insights into the nature of the photocatalysis.展开更多
基金financially supported by the National Natural Science Foundation of China(No.21043006 and 51702205)the Education Department of Guangdong Province(No.2018KTSCX063 and 2013KJCX0081)+2 种基金the Science and Technology Planning Project of Guangdong Province(No.2014A020216045)the 2020 Li Ka Shing Foundation Cross-Disciplinary Research Grant(2020LKSFG09A)the Guangdong Key Discipline Fund at GTIIT。
文摘The conventional p-n heterojunction photocatalysts suffer from the incompatibility between the interfacial charge transfer efficiency and the redox ability of charge carriers.To optimize the interfacial charge transfer of the conventional BiOI/TiO_(2) p-n photocatalyst,we synthesized the BiOI/Bi/TiO_(2) ternary photocatalyst with sandwiched metallic bismuth(Bi~0)by the oxygen-vacancy assisted method.The DFT calculation and structural characterizations confirmed the reaction of the electron-rich oxygen vacancies in the 2D-TiO_(2) nanosheets(TiO_(2)-NS)with the adsorbed BiO~+species.This reaction broke the Bi-O bonds to form Bi^(0) nanoparticles in-situ at the interface but still maintained the p-n heterojunction well.The NO-TPD and XRD analyses for samples correlated the Bi~0 formation with the oxygen vacancy concentrations well.The sandwiched Bi~0 functioned as an electronic transfer mediator like that in the Z-scheme heterostructure.Comparing with 0.20 BiOI/TiO_(2)-NP(NP,Nanoparticles),0.20 BiOI/Bi/TiO_(2)-NS-a(NS,Nanosheet)showed a much improved catalytic performance,i.e.,duplicated apparent quantum yield(AQY)and triplicated reaction rate constant(k).Also,the formation mechanism and the reaction mechanism were investigated in detail.This work provides a new strategy for the improving of the conventional p-n photocatalysts and new insights into the nature of the photocatalysis.