Given their unique structure-dependent properties,strategically designing semiconductor-based photocatalysts,which expose highly reactive crystalline facets,is widely used to tune their performance.Herein,AgBr/Ag/TiO_...Given their unique structure-dependent properties,strategically designing semiconductor-based photocatalysts,which expose highly reactive crystalline facets,is widely used to tune their performance.Herein,AgBr/Ag/TiO_(2){100}nanorods Z-scheme heterojunction composites were prepared via hydrothermal and in situ facet-induced reduction.Transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,electron paramagnetic resonance spectroscopy,and density functional theory calculations reveal that the selective exposure of TiO_(2){100}facets with abundant oxygen vacancies(OV)promotes the formation of metallic silver on the interfaces between AgBr and TiO_(2){100}.Metallic silver can mediate interfacial charge transfer by facilitating the photogenerated carrier recombination of the conduction band of TiO_(2){100}and the valence band of AgBr.As a result,a Z-scheme heterojunction is formed in AgBr/Ag/TiO_(2){100}.The AgBr/Ag/TiO_(2){100}exhibits faster degradation of tetracycline in aqueous solution compared to pristine AgBr,TiO_(2){101},TiO_(2){100}and AgBr/TiO_(2){101}p-n heterojunctions.This is attributed to the effect of the Z-scheme heterojunction on prolonging the lifetime of photogenerated carriers,which is confirmed by femtosecond transient absorption spectroscopy.The photocatalytic mechanism and degradation pathways are discussed along with a toxicity assessment of the intermediates.Overall,this work develops a new approach for designing Z-scheme heterojunction photocatalysts via selective facet control of anatase TiO_(2).展开更多
TiO2 nanotubes were prepared under normal pressure at a temperature of 120 ℃. Ag, Au, Pt nanoparticles supported on TiO2 nanotubes were prepared by m icrowave assisted heating polyol process. TEM images showed that m...TiO2 nanotubes were prepared under normal pressure at a temperature of 120 ℃. Ag, Au, Pt nanoparticles supported on TiO2 nanotubes were prepared by m icrowave assisted heating polyol process. TEM images showed that microwave prepa red Ag, Au, Pt nanoparticles supported on TiO2 nanotubes were small and well dis persed on the surface of the TiO2 nanotubes. UV-Vis absorption spectra showed th at the absorbance of Ag/TiO2 nanotubes and Au/TiO2 nanotubes in the visible ligh t range increased greatly compared to the single titania nanotubes.展开更多
文摘Given their unique structure-dependent properties,strategically designing semiconductor-based photocatalysts,which expose highly reactive crystalline facets,is widely used to tune their performance.Herein,AgBr/Ag/TiO_(2){100}nanorods Z-scheme heterojunction composites were prepared via hydrothermal and in situ facet-induced reduction.Transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,electron paramagnetic resonance spectroscopy,and density functional theory calculations reveal that the selective exposure of TiO_(2){100}facets with abundant oxygen vacancies(OV)promotes the formation of metallic silver on the interfaces between AgBr and TiO_(2){100}.Metallic silver can mediate interfacial charge transfer by facilitating the photogenerated carrier recombination of the conduction band of TiO_(2){100}and the valence band of AgBr.As a result,a Z-scheme heterojunction is formed in AgBr/Ag/TiO_(2){100}.The AgBr/Ag/TiO_(2){100}exhibits faster degradation of tetracycline in aqueous solution compared to pristine AgBr,TiO_(2){101},TiO_(2){100}and AgBr/TiO_(2){101}p-n heterojunctions.This is attributed to the effect of the Z-scheme heterojunction on prolonging the lifetime of photogenerated carriers,which is confirmed by femtosecond transient absorption spectroscopy.The photocatalytic mechanism and degradation pathways are discussed along with a toxicity assessment of the intermediates.Overall,this work develops a new approach for designing Z-scheme heterojunction photocatalysts via selective facet control of anatase TiO_(2).
文摘TiO2 nanotubes were prepared under normal pressure at a temperature of 120 ℃. Ag, Au, Pt nanoparticles supported on TiO2 nanotubes were prepared by m icrowave assisted heating polyol process. TEM images showed that microwave prepa red Ag, Au, Pt nanoparticles supported on TiO2 nanotubes were small and well dis persed on the surface of the TiO2 nanotubes. UV-Vis absorption spectra showed th at the absorbance of Ag/TiO2 nanotubes and Au/TiO2 nanotubes in the visible ligh t range increased greatly compared to the single titania nanotubes.
