Novel BiOI/BiOBr heterojunction photocatalysts with enhanced visible light photocatalytic properties

A novel heterojunction photocatalyst BiOI/BiOBr was synthesized by a simple modified deposition–precipitation method. Several characterization tools including XRD, SEM, HRTEM and UV–vis DRS were employed to study the phase structures, morphologies and optical properties of the samples. BiOI/BiOBr exhibited higher photocatalytic activity than single BiOI and BiOBr for the degradation of methyl orange (MO) under visible light (λ > 420 nm). This result can be due to the formation of the heterojunction between BiOI and BiOBr, which can separate photogenerated carriers efficiently. The photocatalytic mechanism study demonstrates that O2− and h+ are the main reactive species while OH can be negligible.

Graphical abstractNovel BiOI/BiOBr heterojunction photocatalysts were synthesized by a facile modified deposition–precipitation method and exhibited higher photo-activities than single BiOI and BiOBr under visible light irradiation (λ > 420 nm) in the process of methyl orange (MO) degradation. The formation of the BiOI/BiOBr heterojunction is responsible for the enhanced photo-activities of BiOI/BiOBr, which can facilitate separation of photogenerated carriers. The superoxide radical anions (O2−) and holes (h+) were proven to be the main reactive species in the BiOI/BiOBr photocatalysis.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights►BiOI/BiOBr was prepared by a simple modified deposition–precipitation method. ►BiOI/BiOBr displayed higher photocatalytic activity than single BiOI and BiOBr. ►O2− radicals and h+ were proven to be the main reactive species. ►The formation of BiOI/BiOBr heterojunction plays a key role in the photocatalysis.