Synthesis of novel p-n-p BiOBr/ZnO/BiOI heterostructures and their efficient photocatalytic performances in removals of dye pollutants under visible light

Various photocatalysts were synthesized through deposition of BiOBr and BiOI on ZnO in the present research. The formation of heterostructures was studied by different instruments. The photocatalytic performances were studied by degrading different dyes, as water contaminants. The results showed that the ternary BiOBr/ZnO/BiOI (20 %) heterostructure has excellent photocatalytic ability in degradations of methylene blue, fuchsine, rhodamine B, and methyl orange, which was about 12.5, 41.5, 59, and 75-folds as high as the pristine ZnO, respectively. The increased photodegradation ability was ascribed to the more absorption of visible light, large specific surface area, and the construction of p-n-p heterojunctions at the interface of p-BiOBr, n-ZnO, and p-BiOI semiconductors. It was proved that the center dot O-2(-), OH center dot, and h(+) species play important roles in photocatalytic performances. In our opinion, this study provides a new procedure for fabrication of efficient p-n-p heterojunction photocatalysts based on ZnO, which could solve environmental problems.