In Situ Synthesis of All-Solid-State Z-Scheme BiOBr(0.3)I(0.7)/Ag/AgI Photocatalysts with Enhanced Photocatalytic Activity Under Visible Light Irradiation

A series of novel visible light driven all-solid-state Z-scheme BiOBr(0.3)I(0.7)/Ag/AgI photocatalysts were synthesized by facile in situ precipitation and photo-reduction methods. Under visible light irradiation, the BiOBr(0.3)I(0.7)/Ag/AgI samples exhibited enhanced photocatalytic activity compared to BiOBr(0.3)I(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(0.3)I(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 ·O(2)(−) and h(+) are active radicals for photocatalytic degradation and that a small amount of ·OH also participates in the photocatalytic degradation process.