Construction of direct Z-scheme BiOBr/CuI heterojunction for boosting photocatalytic degradation of phenol

Abstract

In this work, direct Z-scheme BiOBr/CuI heterojunctions are successfully synthesized using a simple solvothermal method for the first time. The photocatalytic activity of the BiOBr/CuI composite catalysts is evaluated by the degradation of phenol under visible light. The photocatalytic performance of all the composites is higher than that of the pure components. BiOBr/CuI-1 : 0.8 shows the best photocatalytic performance, which could remove 98.4% phenol in 150 minutes, almost 4.35 and 8.63 times as high as that of pure BiOBr and CuI, respectively. Assisted by XPS, the charge transfer of the composites is investigated. The good photocatalytic performance of the composites is attributed to the Z-scheme charge transfer between BiOBr and CuI. Moreover, the main active species in this system are proved by free radical quenching experiments and EPR, and a possible degradation mechanism is proposed. The degradation products of phenol are analyzed by HPLC-MS and the possible degradation paths are proposed.