In situ fabrication of BiOBrxCl1−x photocatalysts with a regulated electronic structure and enhanced visible light photocatalytic performance

Abstract

A series of BiOBr_xCl_1−x solid solution photocatalysts were constructed, aiming to regulate the electronic structure and visible light response by partially substituting Cl⁻ with Br⁻ for enhancing the photocatalytic RhB degradation performance of BiOCl. BiOBr_0.25Cl_0.75 achieved an optimal degradation efficiency of 96.0% within 100 min of irradiation, which was 1.1 and 1.3 times higher than those of BiOCl (87.7%) and BiOBr (75.7%). Experimental results demonstrated that the improved photocatalytic properties of BiOBr_xCl_1−x are caused by the synergistic effects of stronger oxidation capacity of photogenerated holes, larger surface area and higher separation efficiency, as well as the fast transfer of photogenerated charge carriers. Furthermore, abundant defect centers were produced in BiOBr_0.25Cl_0.75, which could give rise to more reactive sites and electron trap centers to hinder the recombination of photogenerated charge carriers. The results of mechanism analysis indicated that the photocatalytic RhB degradation process in the BiOBr_0.25Cl_0.75 system was dominated by the synergistic effect of photogenerated electrons, holes and ˙O₂⁻.