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

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 m(2) 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.