Uniform flower-like BiOBr/BiOI prepared by a new method: visible-light photocatalytic degradation, influencing factors and degradation mechanism

Abstract

The binary BiOBr/BiOI composite photocatalysts with different molar ratios obtained via a simple one-step solvothermal method were investigated by using XRD, Raman spectroscopy, SEM, EDS, TEM, HR-TEM, BET, UV-vis DRS and PL. The degradation efficiency of uniform flower-like BiOBr/BiOI (3 : 1) is best when the samples were used to degrade RhB solution under visible light irradiation, which is attributed to its uniform particle distribution and the largest specific surface area of 44.21 m² g⁻¹. Compared with the previously synthesized BiOBr/BiOI, the morphology and specific surface area of BiOBr/BiOI (3 : 1) have obvious advantages. The influence factors (pH, NO₃⁻, Cl⁻ and HCO₃⁻) on the photocatalytic performance of BiOBr/BiOI (3 : 1) were explored. The recycling experiments demonstrate that BiOBr/BiOI (3 : 1) composite maintains high photocatalytic activity after eight recycling experiments, and its crystal structure and morphology do not change. In addition, a possible degradation mechanism was also ascertained by radical capture experiments, EPR and semiconductor structure analysis. All results suggest that the uniform flower-like BiOBr/BiOI (3 : 1) composite with high photocatalytic degradation efficiency, excellent recyclability and stability has promising application potential for the photocatalytic degradation of organic compounds in wastewater.