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

Abstract 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.