Reduced graphene oxide as capturer of dyes and electrons during photocatalysis: surface wrapping and capture promoted efficiency

Abstract

To elucidate the roles of graphene in photoelectric events and mass transfer during photocatalytic process is important for engineering graphene-semiconductor hybrid photocatalyst. Here, we demonstrated reduced graphene oxide (RGO) capturing dyes and photoinduced electrons during photocatalytic degradation of organic dyes in water. It captures dyes from water through adsorption and desorption irreversible hysteresis, and captures photoinduced electrons from semiconductor through surface junction. The RGO was attached to the surface of TiO₂ in the form of surface wrapping. After one-step photocatalytic reduction of graphene oxide (GO) and TiO₂ in ethanol–water solvent under UV irradiation, the RGO wrapped TiO₂ hybrid (graphene-w-TiO₂) photocatalyst was obtained. Using visible absorption spectroscopy, we also demonstrated these captured dyes were degraded during photocatalysis. The photocatalytic test showed the RGO significantly improved the photocatalytic activity of this hybrid photocatalyst.