Visible-light-driven Z-scheme rGO/Bi2S3–BiOBr heterojunctions with tunable exposed BiOBr (102) facets for efficient synchronous photocatalytic degradation of 2-nitrophenol and Cr(vi) reduction

Abstract

Fabrication of Z-scheme heterojunctions and crystal facet engineering are effective strategies for enhancing visible-light photocatalytic redox ability. Visible-light-responsive Z-scheme reduced graphene oxide (rGO)/Bi₂S₃–BiOBr heterojunctions with a tunable exposed BiOBr (102) facet and high stability were prepared by a one-pot solvothermal strategy. A graphene oxide (GO) solution acts as a rGO precursor and crystal facet controlling agent of BiOBr (102). The optimized 1% rGO/Bi₂S₃–BiOBr catalyst shows a much higher photocatalytic activity in degrading a single-component 2-nitrophenol (2NP) solution and a reducing single-component Cr(VI) solution than Bi₂S₃, BiOBr and Bi₂S₃–BiOBr. In the mixture solution of 2NP and Cr(VI), 2NP degradation and Cr(VI) reduction occur simultaneously, and the Cr(VI) reduction efficiency and 2NP degradation efficiency reached 95% and 67%, respectively. The synergism of rGO/Bi₂S₃–BiOBr for simultaneous 2NP degradation and Cr(VI) reduction can be attributed to the efficient production of electrons and reactive oxygen species. This work sheds light on the design of facet-dependent Z-scheme photocatalysts to advance photocatalytic redox capability.