Novel Z-scheme visible-light photocatalyst based on CoFe2O4/BiOBr/Graphene composites for organic dye degradation and Cr(VI) reduction

In the present study, a novel visible-light Z-scheme photocatalyst based on BiOBr/CoFe2O4/graphene ternary structure was prepared through a hydrothermal approach. The morphology and structure of the prepared photocatalyst were characterized, and the optical properties of the photocatalyst were investigated as well. Afterwards, the photocatalytic performance of the Z-scheme photocatalyst were evaluated through degrading rhodamine B dye and reducing Cr(VI) under visible light irradiation. Compared with pure BiOBr and BiOBr/CoFe2O4 binary composites, the prepared BiOBr/CoFe2O4/graphene ternary exhibited higher photo-degradation and photo-reduction efficiency. It was also found that the holes were the main active species which were generated during the photocatalysis process. Due to the existence of conductive graphene, the photo-generated active species could be effectively stabilized and quickly transferred. Moreover, the prepared photocatalyst showed very promising recyclable stability, in which the photocatalytic performance of the composites barely decreased after five consecutive circles. The present study provides a new insight in designing and constructing high-efficient and recyclable photocatalyst for aqueous pollutant removal.