摘要
All-solid-state Z-scheme photocatalysts,containing Cu_(2)O,TiO_(2)(rutile),and Au as the elec-tron mediator,were prepared and applied to the reduction of Cr(Ⅵ)in aqueous solutions.The Cu_(2)O-Au-TiO_(2) composites were prepared by loading Au core-Cu_(2)O shell hemisphere particles on TiO_(2)(rutile)nanorods using a two-step photocatalytic deposition process.Un-der ultraviolet-visible(UV-vis)light illumination,the Cu_(2)O-Au-TiO_(2) composites exhibited higher photocatalytic Cr(Ⅵ)reduction activities than those exhibited by single TiO_(2)(rutile)and Cu_(2)O.In this reaction,a precipitate containing Cr,which was considered to be Cr(OH)_(3),was deposited site-selectively on the Au core-Cu_(2)O shell particles of the composites,indi-cating that the reduction site of the composite was Cu_(2)O,and the reaction proceeded accord-ing to the Z-scheme.The Cu_(2)O-Au-TiO_(2) composites also exhibited photocatalytic activity under visible light illumination.The oxidation state of Cu in the Cu_(2)O-Au-TiO_(2) composite gradually changed from Cu(Ⅰ)to Cu(Ⅱ)during the photocatalytic Cr(Ⅵ)reduction.However the composite maintained its high photocatalytic performance even after oxidation.The role of Au in the Cu_(2)O-Au-TiO_(2) composite was examined by comparing the properties of the Cu_(2)O-Au-TiO_(2) composite with those of the Cu_(2)O-TiO_(2) composite prepared via direct Cu_(2)O deposition on TiO_(2).
基金
This work was supported by the Japan Society for the Promotion of Science(JSPS)KAKENHI(No.JP 19K05057).
