A novel direct Z-scheme heterojunction BiFeO3/ZnFe2O4 photocatalyst for enhanced photocatalyst degradation activity under visible light irradiation

In recent years, inhibition of photoinduced electron and hole recombination is considered as a breakthrough to improve the photocatalytic degradation of pollutants. In this study, we successfully loaded ZnFe2O4 (ZFO) microsphere onto BiFeO3 (BFO) microcubes via a simple hydrothermal method, and intimate interface between BFO and ZFO was constructed. Under the effect of heterojunction between BFO and ZFO, the recombination rate of photogenerated electron-hole pairs was decreased significantly, leading to the enhanced photocatalytic effect. The photocatalytic experiments show that the degradation efficiency of BFO/ZFO-10% composite for tetracycline and methylene blue are 1.63 and 1.38 times higher than that of pure BFO. In addition, four cycles experiment also proved that BFO/ZFO has good stability and excellent magnetic recovery properties. A possible carrier transfer path on the base of the direct Z-scheme mechanism in composite was proposed. This study provides a useful guide toward the design of the highly efficient and magnetic collectable photocatalysts by the introduction of magnetic component and the construction of heterojunction, and as-synthesized BFO/ZFO was proved to be a promising photocatalyst for the elimination of toxic organic molecules in groundwater.