A simple calcination method was employed to prepare a Z-scheme N-doped K4Nb6O17/g-C3N4(KCN)heterojunction photocatalyst,in which the electronic structure of K4Nb6O17 was regulated by N-doping,and g-C3N4 was formed bot...A simple calcination method was employed to prepare a Z-scheme N-doped K4Nb6O17/g-C3N4(KCN)heterojunction photocatalyst,in which the electronic structure of K4Nb6O17 was regulated by N-doping,and g-C3N4 was formed both on the surface and within the interlayer spaces of K4Nb6O17.The KCN composite showed profoundly improved photocatalytic activity for both H2 generation and RhB degradation compared to its counterparts.This improved performance was attributed to the synergistic effects of N-doping,which broadened its light harvesting ability,and heterojunction formation,which increased the charge separation rate.The relatively low BET specific surface area of the KCN composite had little effect on its photocatalytic activity.Based on ESR spectroscopy studies,•O2^−,•OH,and h^+are the main active species in the photocatalytic degradation of RhB.Thus,it is reasonable to propose a Z-scheme photocatalytic mechanism over the KCN composite,which exhibits the dual advantages of efficient charge separation and high redox ability.Our work provides a simple approach for constructing large-scale Z-scheme heterojunction photocatalysts with high photocatalytic performance.展开更多
An octahedral Nb6 structural unit with space aromaticity is identified for the first time in a transition–metal monoxide crystal Nb3O3 by ab initio calculations.The strong Nb–Nb metallic bonding facilitates the form...An octahedral Nb6 structural unit with space aromaticity is identified for the first time in a transition–metal monoxide crystal Nb3O3 by ab initio calculations.The strong Nb–Nb metallic bonding facilitates the formation of stable octahedral Nb6 structural units and the release of delocalization energy.Moreover,the Nb atoms in continuously connected Nb6 structural units share their electrons with each other in a continuous space of framework,so that the electrons are uniformly distributed.The newly discovered aromaticity in the octahedral Nb6 structural units extends the range of aromatic compounds and broadens our vision in structural chemistry.展开更多
文摘A simple calcination method was employed to prepare a Z-scheme N-doped K4Nb6O17/g-C3N4(KCN)heterojunction photocatalyst,in which the electronic structure of K4Nb6O17 was regulated by N-doping,and g-C3N4 was formed both on the surface and within the interlayer spaces of K4Nb6O17.The KCN composite showed profoundly improved photocatalytic activity for both H2 generation and RhB degradation compared to its counterparts.This improved performance was attributed to the synergistic effects of N-doping,which broadened its light harvesting ability,and heterojunction formation,which increased the charge separation rate.The relatively low BET specific surface area of the KCN composite had little effect on its photocatalytic activity.Based on ESR spectroscopy studies,•O2^−,•OH,and h^+are the main active species in the photocatalytic degradation of RhB.Thus,it is reasonable to propose a Z-scheme photocatalytic mechanism over the KCN composite,which exhibits the dual advantages of efficient charge separation and high redox ability.Our work provides a simple approach for constructing large-scale Z-scheme heterojunction photocatalysts with high photocatalytic performance.
基金financially supported by National Key R&D Program of China(2016YFB0700600)Soft Science Research Project of Guangdong Province(2017B030301013)Shenzhen Science and Technology Research Grant(ZDSYS201707281026184).
文摘An octahedral Nb6 structural unit with space aromaticity is identified for the first time in a transition–metal monoxide crystal Nb3O3 by ab initio calculations.The strong Nb–Nb metallic bonding facilitates the formation of stable octahedral Nb6 structural units and the release of delocalization energy.Moreover,the Nb atoms in continuously connected Nb6 structural units share their electrons with each other in a continuous space of framework,so that the electrons are uniformly distributed.The newly discovered aromaticity in the octahedral Nb6 structural units extends the range of aromatic compounds and broadens our vision in structural chemistry.
