S-scheme heterojunctions can preserve strong redox capacity on the basis of achieving spatial separation of photogenerated carriers.Therefore,a deep comprehension of the photoinduced charge transfer dynamics in S-sche...S-scheme heterojunctions can preserve strong redox capacity on the basis of achieving spatial separation of photogenerated carriers.Therefore,a deep comprehension of the photoinduced charge transfer dynamics in S-scheme heterostructures is vital to enhancing photocatalytic properties.Herein,SnO_(2)/BiOBr S-scheme heterojunctions with tight contact are fabricated with in situ hydrothermal method.The optimal SnO_(2)/BiOBr exhibits excellent photocatalytic performance for CO_(2)reduction,with yields of CO and CH4 of 345.7 and 6.7μmol∙g^(–1)∙h^(–1),which are 5.6 and 3.7 times higher than those of the original BiOBr.The photoinduced charge transfer mechanism and dynamics of SnO_(2)/BiOBr S-scheme heterostructure are characterized by in situ X-ray photoelectron spectrum(XPS)and femtosecond transient absorption spectroscopy(fs-TA).A new fitted lifetime of photogenerated carriers are observed,which could be attributed to interfacial electron transfer of S-scheme heterojunction,further illustrating an ultrafast transfer channel for photoelectrons from SnO_(2)conduction band to BiOBr valence band.As a result,the powerful reduced electrons in BiOBr conduction band and the powerful oxidation holes in SnO_(2)valence band are retained.This work provides profound comprehension of photoinduced charge transfer mechanism of S-scheme heterojunction.展开更多
文摘S-scheme heterojunctions can preserve strong redox capacity on the basis of achieving spatial separation of photogenerated carriers.Therefore,a deep comprehension of the photoinduced charge transfer dynamics in S-scheme heterostructures is vital to enhancing photocatalytic properties.Herein,SnO_(2)/BiOBr S-scheme heterojunctions with tight contact are fabricated with in situ hydrothermal method.The optimal SnO_(2)/BiOBr exhibits excellent photocatalytic performance for CO_(2)reduction,with yields of CO and CH4 of 345.7 and 6.7μmol∙g^(–1)∙h^(–1),which are 5.6 and 3.7 times higher than those of the original BiOBr.The photoinduced charge transfer mechanism and dynamics of SnO_(2)/BiOBr S-scheme heterostructure are characterized by in situ X-ray photoelectron spectrum(XPS)and femtosecond transient absorption spectroscopy(fs-TA).A new fitted lifetime of photogenerated carriers are observed,which could be attributed to interfacial electron transfer of S-scheme heterojunction,further illustrating an ultrafast transfer channel for photoelectrons from SnO_(2)conduction band to BiOBr valence band.As a result,the powerful reduced electrons in BiOBr conduction band and the powerful oxidation holes in SnO_(2)valence band are retained.This work provides profound comprehension of photoinduced charge transfer mechanism of S-scheme heterojunction.
