Design of novel structured Au/g-C3N4 nanosheet/reduced graphene oxide nanocomposites for enhanced visible light photocatalytic activities

Abstract

In order to surmount the intrinsic disadvantages of raw g-C₃N₄, we demonstrate simple thermal oxidation exfoliation and facile in situ photoreduction methods to fabricate Au/g-C₃N₄ nanosheet/reduced graphene oxide (Au/CNNS/rGO) photocatalysts. During the preparation, g-C₃N₄ was exfoliated to ultrathin nanosheets, and the deposition of Au and reduction of graphene oxide (GO) were accomplished simultaneously. Remarkably, the monodispersed Au nanoparticles were well anchored on the surface of the CNNSs and rGO was decorated on the opposite surface of the CNNSs. This novel structure bidirectionally promotes the transfer of photogenerated electrons. The H₂ evolution rate of optimal Au/CNNS/rGO is 9.6 times higher and the methylene blue degradation rate is 6 times higher than those of pure g-C₃N₄ under visible light irradiation. The enhancement of photocatalytic activities could be attributed to the novel structure of the nanocomposite, the surface plasmon resonance effect of Au, the high electron mobility of rGO and the large surface area of CNNSs.