Influence of interface combination of RGO-photosensitized SnO2@RGO core-shell structures on their photocatalytic performance

SnO2@reduced graphene oxide (RGO) core-shell structures were successfully synthesized by two different strategies (electrostatic interaction method and direct chemical bonding reaction method). The investigation of morphologies and microstructures showed that RGO was wrapped tightly on the surface of SnO2 microspheres with different interface combinations, i.e., electrostatic interaction and chemical bonding. Raman spectroscopy and photoluminescence (PL) spectra demonstrated that graphene as a photosensitizer could transfer photogenerated electrons to the conduction band (CB) of SnO2 and receive holes from the valence band (VB) of SnO2, resulting in the separation of photogenerated electron -hole pairs. The photocatalytic activity of the synthesized composites was evaluated by the photodegradation of methyl orange (MO) under ultraviolet (UV) light irradiation. It was found that SnO2@RGO with chemical bonding interface combination exhibited higher photodegradation rate (k= 0.038 min(-1)) than those with electrostatic interaction interface combination (k= 0.021 min(-1)) and pure SnO2 (k= 0.010 min(-1)). The enhanced photocatalytic activity could be attributed to the photosensitization of RGO and the intimate interface combination between SnO2 and RGO. (C) 2016 Elsevier B.V. All rights reserved.