Enhanced photocatalytic hydrogen evolution from reduced graphene oxide-defect rich TiO2-x nanocomposites

Abstract

Solar-driven photocatalytic hydrogen generation by splitting water molecules requires an efficient visible light active photocatalyst. This work reports an improved hydrogen evolution activity of visible light active TiO2-x photocatalyst by introducing reduced graphene oxide via an eco-friendly and cost-effective hydrothermal method. This process facilitates graphene oxide reduction and incorporates intrinsic defects in TiO2 lattice at a one-pot reaction process. The characteristic studies reveal that RGO/TiO2-x nanocomposites were sufficiently durable and efficient for photocatalytic hydrogen generation under the visible light spectrum. The altered band gap of TiO2-x rationally promotes the visible light absorption, and the RGO sheets present in the composites suppresses the electron-hole recombination, which accelerates the charge transfer. Hence, the noble metal-free RGO/TiO2-x photocatalyst exhibited hydrogen production with a rate of 13.6 mmol h−1g−1cat. under solar illumination. The appreciable photocatalytic hydrogen generation activity of 947.2 μmol h−1g−1cat with 117 μAcm−2 photocurrent density was observed under visible light (>450 nm).