Enhanced Daylight-Induced Photocatalytic Activity of Solvent Exfoliated Graphene (SEG)/ZnO Hybrid Nanocomposites toward Degradation of Reactive Black 5

Abstract

A series of SEG/ZnO photocatalysts with different ratios of Zn(NO 3 ) 2 precursor was synthesized via a facile chemical deposition-calcination approach using solvent exfoliated graphene (SEG) as a precursor of graphene, Zn(NH 3 ) 4 CO 3 as a precursor of ZnO, NaOH as a precipitating agent, and poly(vinylpyrrolidone) as an interface linker. The photocatalytic activity and stability of SEG/ZnO were evaluated by the degradation of Reactive Black 5 (RB5) under visible light. In comparison to pure SEG and ZnO, SEG/ZnO nanocomposites displayed a remarkable RB5 degradation of 97.0% with a rate constant of 0.0199 min –1 under a low-power 15 W energy-saving light bulb for 3 h. The optimum ZnO content was 69.0 wt %, which demonstrated a 10-fold enhancement after graphene hybridization than that for pure ZnO. This was accredited to effective dye sensitization and suppressed electron–hole recombination via SEG as electron storage. Lastly, a visible-light photocatalytic mechanism for the photoactivity was explored.