Interfacial and electronic band structure optimization for the adsorption and visible-light photocatalytic activity of macroscopic ZnSnO3/graphene aerogel

A macroscopic monolithic ZnSnO3/reduced graphene oxide aerogel (ZGA) composite was prepared and showed excellent adsorption and visible-light photocatalytic degradation activity for ciprofloxacin (CIP) wastewater. Especially, when the mass ratio of ZnSn(OH)6 to graphene oxide (GO) is 1:2 (ZGA-4), the removal efficiency of CIP is almost reach 100%. The enhanced photoactivity of ZGA can be attributed to the optimized interfacial and electronic band structure reducing the recombination of photogenerated e−-h+ pairs to produce more ·O2− and ·OH active species, which were confirmed by series of characterization techniques combine with density functional theory (DFT) calculations. Moreover, ZGA also exhibits satisfactory photostability, 98% CIP and the biological toxicity of CIP to Escherichia coli DH5a have been basically eliminated after four-cycle photocatalytic degradation. •Visible-light response macroscopic monolithic ZnSnO3/graphene aerogel was prepared.•ZGA exhibits excellent photocatalytic and recycle stability for CIP degradation.•Interfacial bonding regulated the electronic band structure of the ZGA composite.•Experimental data combine with DFT calculation confirmed the conjecture.•The biological toxicity of CIP to Escherichia coli DH5a has been eliminated.