Simple Fabrication of Visible Light-Responsive Bi-BiOBr/BiPO4 Heterostructure with Enhanced Photocatalytic Activity

Abstract

A Bi-BiOBr/BiPO₄ heterojunction structure was successfully synthesized via a two-step solvothermal method with ethylene glycol as a reducer. Little BiPO₄ irregular polyhedrons and little metal Bi spherical nanoparticles were uniformly dispersed on the surface of BiOBr nanosheets with intimate contact and formed a heterojunction structure between BiPO₄ and BiOBr. It was found that Bi-BiOBr/BiPO₄ had a significant improvement in photocatalytic performance for RhB degradation compared to bare BiOBr and BiPO₄. The photocatalytic degradation rate constant of 0.2-Bi/BiOBr/BiPO₄ was 1.44h^-1, which was 3.8 times and 14.2 times more than that of bare BiOBr and BiPO₄, respectively. This is attributed to the formation of a ternary heterojunction, which benefits the separation of photogenerated electron-hole pairs. Furthermore, with the introduction of metal Bi, the SPR effect of metal Bi can effectively improve the absorption ability of Bi-BiOBr/BiPO₄ photocatalyst, resulting in enhanced photoactivity. In this work, the mechanism of photocatalytic degradation was studied by using the photochemical technique and the capture experiment of active species, and it was revealed that h⁺ and ^⋅O₂^- played a major role in the photocatalytic process.