Photocatalytic degradation of 2-Mercaptobenzothiazole by a novel Bi2WO6 nanocubes/In(OH)3 photocatalyst: Synthesis process, degradation pathways, and an enhanced photocatalytic performance mechanism study

Abstract

Designing and developing an efficient photocatalytic system for degrading organic pollutants was a research hotspot in the field of environmental governance. In this study, a novel Bi2WO6/In(OH)3 composite photocatalyst was first fabricated via facile calcination-hydrothermal synthesis method. The 9-Bi2WO6/In(OH)3 composite had superior photocatalytic performance for degrading the 2-Mercaptobenzothiazole (MBT) under visible-light irradiation. The degradation rate constant of 9-Bi2WO6/In(OH)3 was 0.02192 min−1, which was 2.3 times than that of pure Bi2WO6 (0.00948 min−1). The improvement in photocatalytic performance was due to the synergistic effect of the surface heterojunction and the electron-transfer medium. The density functional theory (DFT) showed that the difference in energy levels between the conduction bands and valence bands of Bi2WO6 nanocubes (010) and (001) could build the surface heterojunction, which was in favor to promote the electron-hole pairs separation. And the In(OH)3 not only acted as a supporter to prevent the agglomeration of small size Bi2WO6 nanocubes, but also served as electron-transfer mediator to inhibit the recombination of electrons and holes. This study provided a reference value for the development and utilization of Bi-based photocatalysts. Considering the properties and structural characteristics of Bi-based photocatalysts and hydroxides, Bi2WO6/In(OH)3 composite photocatalysts were design reasonably, which provided a variety of the types of photocatalysts.