title: Composition dependence of the photocatalytic activities of BiOCl(1-x)Br(x) solid solutions under visible light.
abstract: We prepared BiOCl(1-x)Br(x) (x=0-1) solid solutions and characterized their structures, morphologies, and photocatalytic properties by X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy, Raman spectroscopy, photocurrent and photocatalytic activity measurements and also by density functional theory calculations for BiOCl, BiOBr, BiOCl(0.5)Br(0.5). Under visible-light irradiation BiOCl(1-x)Br(x) exhibits a stronger photocatalytic activity than do BiOCl and BiOBr, with the activity reaching the maximum at x=0.5 and decreasing gradually as x is increased toward 1 or decreased toward 0. This trend is closely mimicked by the photogenerated current of BiOCl(1-x)Br(x) , indicating that the enhanced photocatalytic activity of BiOCl(1-x)Br(x) with respect to those of BiOCl and BiOBr originates from the trapping of photogenerated carriers. Our electronic structure calculations for BiOCl(0.5)Br(0.5) with the anion (O(2-), Cl(-), Br(-)) and cation (Bi(3+)) vacancies suggest that the trapping of photogenerated carriers is caused most likely by Bi(3+) cation vacancies, which generate hole states above the conduction band maximum.
authors: State Key Lab of Crystal Materials, Shandong University, Jinan 250100, PR China.
authors: Yuanyuan
authors: Y
authors: Liu
authors: Won-Joon
authors: WJ
authors: Son
authors: Jibao
authors: J
authors: Lu
authors: Baibiao
authors: B
authors: Huang
authors: Ying
authors: Y
authors: Dai
authors: Myung-Hwan
authors: MH
authors: Whangbo