BiOBr/ZnMoO₄ Step-scheme Heterojunction: Construction and Photocatalytic Degradation Properties

Abstract

Photocatalysis is widely used for the removal of refractory organic pollutants in water, but the catalytic activity of semiconductor photocatalysts is significantly inhibited due to the high recombination rate of photogenerated electrons and holes. In this study, an S-scheme BiOBr/ZnMoO 4 composite was successfully prepared by a facile solvothermal method. The structure analysis, in-situ XPS, work function test, free radical capture and ESR experiment confirmed that the BiOBr/ZnMoO 4 composite formed an S-scheme heterojunction. The experimental results show that BiOBr/ZnMoO 4 heterojunction with appropriate ZnMoO 4 content can significantly improve the photocatalytic performance of BiOBr. Compared with pure BiOBr and ZnMoO 4 , 15% BiOBr/ZnMoO 4 exhibits the best photocatalytic activity under visible light irradiation, and the photocatalytic degradation rate of bisphenol A reaches 85.3% (90 min). The rate constants of photodegradation of ciprofloxacin are 2.6 times that of BiOBr and 484 times that of ZnMoO 4 , respectively. This can be attributed to the tight interfacial bonding between BiOBr and ZnMoO 4 and 第 1 期 马心全, 等: S 型异质结 BiOBr/ZnMoO 4 的构建及光催化降解性能研究 63 the formation of S-scheme heterojunction, which enables the efficient spatial separation and transfer of photogenerated carriers. This work provides a simple and efficient method for the directional synthesis of Bi-based S-scheme heterojunction photocatalytic materials, and provides a new theory and experimental basis for further understanding of the structure-activity relationship of Bi-based multi-heterojunction photocatalytic materials.