In Situ Synthesis of All-Solid-State Z-Scheme BiOBr0.3I0.7/Ag/AgI Photocatalysts with Enhanced Photocatalytic Activity Under Visible Light Irradiation

Abstract

A series of novel visible light driven all-solid-state Z-scheme BiOBr_0.3I_0.7/Ag/AgI photocatalysts were synthesized by facile in situ precipitation and photo-reduction methods. Under visible light irradiation, the BiOBr_0.3I_0.7/Ag/AgI samples exhibited enhanced photocatalytic activity compared to BiOBr_0.3I_0.7 and AgI in the degradation of methyl orange (MO). The optimal ratio of added elemental Ag was 15%, which degraded 89% of MO within 20 min. The enhanced photocatalytic activity of BiOBr_0.3I_0.7/Ag/AgI can be ascribed to the efficient separation of photo-generated electron-hole pairs through a Z-scheme charge-carrier migration pathway, in which Ag nanoparticles act as electron mediators. The mechanism study indicated that ·O₂^- and h⁺ are active radicals for photocatalytic degradation and that a small amount of ·OH also participates in the photocatalytic degradation process.