Composition Dependence of the Photocatalytic Activities of BiOCl_1−xBr_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.

Structure-Dependent Photocatalytic Performance of BiOBrxI1−x Nanoplate Solid Solutions

“…In the same way, the cell parameters of all the samples gradually increase with I content increasing, as listed in Table 1. These regular changes in XRD peaks and cell parameters as a function of I content strongly declare that the obtained BiOBr x I 1−x products belong to a group of solid solutions [27]. In addition, there are no other diffraction peaks of impurity, which implies that all the atoms entered into the crystal lattice and the stoichiometric value x in BiOBr x I 1−x was accurately determined by the initial proportion of Br and I sources in the preparation procedure [36,39].…”

Solvothermal synthesis of Bi24O31ClxBr10−x solid solutions with enhanced visible light photocatalytic property

“…Fig. 6a [20]. Considering that there may be photosensitization in the degradation of RhB, the photocatalytic activity was also evaluated by the degradation of phenol.…”

Enhanced p-cresol photodegradation over BiOBr/Bi2O3 in the presence of rhodamine B

“…17 In fact, bismuth salts are widely used in pharmaceutical products as antacids and in the treatment of peptic ulcers. Besides the ternary compounds, mixtures and composites such as NaBiO 3 /BiOCl, 18 BiOI/ BiOCl, 19,20 BiOCl/BiOBr [21][22][23][24][25] and Bi/BiOBr 26 have been investigated for their photoactivity.…”