Enhancement of visible photocatalytic performances of a Bi2MoO6–BiOCl nanocomposite with plate-on-plate heterojunction structure

Abstract

A visible-light-sensitive Bi₂MoO₆–BiOCl heterojunction photocatalyst was synthesized via a hydrothermal process. The as-prepared Bi₂MoO₆–BiOCl composite shows an irregular multi-plate structure with length ranging from 100 nm to 1 μm, indicating a possibility of the plate-on-plate structure by placing Bi₂MoO₆ and BiOCl nanoplates over each other. The Bi₂MoO₆–BiOCl photocatalyst not only had a good visible-light photocatalytic performance, but also exhibited higher photocatalytic activity than pure BiOCl and Bi₂MoO₆. The optimal Bi₂MoO₆ content for the photocatalytic activity of the Bi₂MoO₆–BiOCl composites is 30%. Compared to pure Bi₂MoO₆ the photoactivity of the Bi₂MoO₆–BiOCl composites is almost 2.0 times higher for the RhB photodegradation, and 1.5 times higher for the phenol photodegradation under visible light irradiation. The photocatalytic mechanism was elucidated via active species trapping experiments and ESR. The ˙OH and ˙O₂⁻ played the key roles in the degradation of RhB via the Bi₂MoO₆–BiOCl composite. Finally, the possible charge transfer mechanism of the enhanced visible light photocatalytic activity was proposed.