Graphene sheets-based Ag@Ag3PO4 heterostructure for enhanced photocatalytic activity and stability under visible light

We designed the reduced graphene oxide (RGO)-based Ag@Ag3PO4 hetero-photocatalyst by coprecipitation and photoreduction. The graphene sheets are fully coated with Ag@Ag3PO4 nanocrystals with an average diameter of 200 nm. Ag@Ag3PO4/RGO hetero-photocatalyst showed strong absorbance in the visible region and low recombination rate of holes and electrons. Compared with Ag@Ag3PO4, Ag3PO4 and Ag3PO4/GO, Ag@Ag3PO4/RGO hetero-photocatalyst exhibited greatly enhanced photocatalytic activity under visible-light irradiation for the photodegradation of not only cationic dye (rhodamine B) but also anionic dye (methyl orange), which is usually difficult to be degraded over other catalysts. Moreover, the hetero-photocatalyst can be used repetitively with a high photocatalytic activity. The mechanism was explored and confirmed, showing that the improvements are attributed to the effective charge transfer from Ag3PO4 nanocrystals to RGO through Ag nanoparticles, which hinders the recombination of electron/hole pairs and the photocorrosion of Ag3PO4. This study could provide new insights in the design and fabrication of highly efficient visible-light-driven novel photocatalysts for solving energy and environmental problems. (C.) 2013 Elsevier B.V. All rights reserved.