Photocatalytic degradation of 2-Mercaptobenzothiazole by a novel Bi ₂ WO ₆ nanocubes/In(OH) ₃ photocatalyst: Synthesis process, degradation pathways, and an enhanced photocatalytic performance mechanism study

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 Bi ₂ WO ₆ /In(OH) ₃ composite photocatalyst was first fabricated via facile calcination-hydrothermal synthesis method. The 9-Bi ₂ WO ₆ /In(OH) ₃ composite had superior photocatalytic performance for degrading the 2-Mercaptobenzothiazole (MBT) under visible-light irradiation. The degradation rate constant of 9-Bi ₂ WO ₆ /In(OH) ₃ was 0.02192 min ⁻¹ , which was 2.3 times than that of pure Bi ₂ WO ₆ (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 Bi ₂ WO ₆ 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 Bi ₂ WO ₆ 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, Bi ₂ WO ₆ /In(OH) ₃ composite photocatalysts were design reasonably, which provided a variety of the types of photocatalysts.