Self-assembled hierarchical Bi12TiO20–graphene nanoarchitectures with excellent simulated sunlight photocatalytic activity

Abstract

A series of hierarchical Bi₁₂TiO₂₀–graphene nanoarchitectures (Bi₁₂TiO₂₀–GR) with GR loadings from 1% to 10% are fabricated by a single-step solvothermal treatment technique, and the intimate interfacial contact between flexible GR sheets and flower-like Bi₁₂TiO₂₀ nanocrystals is observed in the Bi₁₂TiO₂₀–GR composites. As a novel composite photocatalyst, Bi₁₂TiO₂₀–GR with GR loading of 2% possesses the highest simulated sunlight photocatalytic activity towards the degradation of two typical organic pollutants, methyl orange (MO) and p-nitrophenol (PNP). Furthermore, the separation and transportation of the photogenerated carriers in the simulated sunlight-irradiating Bi₁₂TiO₂₀–GR system is studied, meanwhile, the active species (h_VB⁺, O₂˙⁻ and ˙OH) generated in the Bi₁₂TiO₂₀–GR-photocatalyzed PNP degradation system are identified by free radical and hole scavenging experiments. Based on the experimental and theoretical results, the mechanism and pathway of photocatalytic degradation of PNP in the simulated sunlight-irradiating Bi₁₂TiO₂₀–GR system are proposed.