Photo-assisted synthesis of Ag3PO4/reduced graphene oxide/Ag heterostructure photocatalyst with enhanced photocatalytic activity and stability under visible light

A novel Ag3PO4/reduced graphene oxide/Ag nanocrystals (Ag3PO4/RGO/Ag) heterostructure photocatalyst has been synthesized using a facile photo-assisted reduction method for the first time. The Ag3PO4/RGO/Ag that consists of close chemical bonding between RGO and Ag3PO4 nanoparticles as well as dispersive plasmonic Ag nanocrystals on the RGO sheets exhibited superior photocatalytic activity and stability to bare Ag3PO4, Ag/Ag3PO4 and Ag3PO4/GO in degradation of Rhodamine B and phenol under visible light. It is suggested that the photo-generated electrons in Ag3PO4 can be transferred to RGO/Ag, leading to efficient separation and transfer of electron-hole pairs. Meanwhile, under light irradiation, the plasmonic Ag nanocrystals also generate electron-hole pairs through surface plasmon resonance (SPR), in which the active electrons can facilitate the formation of additional active species of O-2 center dot(-) for photocatalysis whereas the holes can be filled by electrons from RGO. As a result, both the photocorrosion of Ag3PO4 and the recombination of electron-hole pairs are suppressed due to the special electron transfer route of Ag3PO4 -> RGO -> Ag in the heterostructure. This work suggests that the reasonable combination of semiconductors and graphene decorated with noble metallic nanocrystals can provide a versatile strategy for the synthesis of high efficient heterostructed photocatalysts. (C) 2014 Elsevier B.V. All rights reserved.