BiOBrxI(1-x) solid solution with oxygen vacancies boosting the photocatalytic degradation of multiple pollutants

In this work, we prepared BiOBrxI(1-x) solid-solution with abundant oxygen vacancies by a facile hydrothermal method. The efficiency in the photocatalytic degradation of rhodamine B with BiOBr0.5I0.5 as photocatalyst was determined to be more than 99.9% in 12 min under visible light irradiation, which was 2 and 5 times higher than pure BiOBr and BiOI, respectively. Further tests revealed that BiOBr0.5I0.5 sample was able to efficiently decompose other contaminants including CrVI, tetracycline hydrochloride, methyl orange and methylene blue. In addition, the resultant solution after the degradation process has considerable biocompatibility through the growth of wheat seeds. Various spectroscopic characterizations and electrochemical studies were performed including PL, EIS etc. The excellent photocatalytic performance can be ascribed to the effective separation of photogenerated carriers, where the synergistic impact of solid solution and oxygen vacancies played an essential role. The band structure of the sample was established and the reaction mechanism was discussed. The atomically mixed oxyhalide is proved to be a promising photocatalyst for practical environmental applications.