Surface functionalization of hierarchical BiOBr/ZnWO4 heterojunctions as visible-light driven photocatalysts

Abstract

A p–n BiOBr/ZnWO₄ (BZ) heterojunction was synthesized and used for the photocatalytic degradation of RhB in aqueous solution under visible-light irradiation. Notably, an optimized 0.15BZ composite (mole ratio) exhibited excellent photocatalytic activity, which is 14.7 times higher than that of bare ZnWO₄. The integration of p–n heterojunction at the interface of hierarchical nanoflake-assembled BiOBr flowers and nanoflake-assembled yolk–shell microspheres of ZnWO₄ can efficiently promote charge separation and migration, thus significantly improving the photocatalytic performance. Electron paramagnetic resonance (EPR) spectra proved that ·OH radicals were the key reactive components. Moreover, a degradation efficiency of 89.8% was maintained after four cycles, representing good durability for the BZ photocatalyst. This work offers a reasonable way for the economic synthesis of heterojunction materials, and the high-efficiency and chemically stable BiOBr/ZnWO₄ heterojunction composite might act as a promising photocatalyst in water purification applications.