Significant enhancement in the visible light photocatalytic properties of BiFeO₃–graphene nanohybrids

Abstract

Graphene-based visible light photocatalysts have been actively pursued in recent years due to the high charge mobility of graphene and hence, the lower recombination rate of electron–hole pairs. BiFeO3 with a band gap in the visible range is considered a promising candidate as an oxide photocatalyst. In this contribution, BiFeO3–graphene nanohybrids are fabricated via facile hydrothermal treatments. The morphology and band structure of BiFeO3 are modulated by graphene. Nanohybrids with BiFeO3 nanocrystallites of ∼100 nm uniformly decorated on graphene nanosheets are successfully synthesized, which exhibit a band gap of ∼1.78 eV. Chemical bonding between BiFeO3 and graphene is characterized by XPS analysis. Significant enhancement in the visible light photocatalytic performance is achieved in the BiFeO3–graphene nanohybrids. The rate for the photo-degradation of Congo Red under visible light is six times that for BiFeO3 particles, which is attributed to the combined effects of modulated band gap and covalent bonding between BiFeO3 and graphene.