A novel Type-II Bi-based oxyhalide: Bi4O5I2/BiOBr microspheres for improved photocatalytic performance

Abstract

Enhancing the oxidation and reduction capabilities of semiconductor catalysts through Type-II heterojunction engineering is a viable approach. A new photocatalytic material, Bi4O5I2/BiOBr, has been successfully developed by integrating Bi4O5I2 into the structure of BiOBr using a straightforward solvothermal technique. The significantly reducing electrons of Bi4O5I2 and the initially strongly oxidizing holes of BiOBr are effectively preserved in the hybrid material through a Type-II heterojunction. The formation of a heterostructure facilitates the movement and separation of photogenerated carriers. The 0.3 wt% Bi4O5I2/BiOBr exhibited the highest catalytic activity for degrading organic pollutants under visible light, with •O2− and h+ as the primary active species. The mechanism preserves the charge carrier's robust redox capability by utilizing the remarkably stable and reusable Bi4O5I2/BiOBr composite material for environmental protection. A hypothesis was proposed regarding the potential performance of Bi4O5I2/BiOBr under visible light mechanisms as direct Type-II heterojunction photocatalytic materials.