Improved interfacial bonding of graphene-TiO2 with enhanced photocatalytic reduction of CO2 into solar fuel

Abstract

This study focuses on the improvement in the interfacial bonding of reduced graphene oxide (rGO) and titanium dioxide (TiO2) and important factors which contributed towards the enhanced photocatalytic activity of rGO/TiO2 photocatalyst. A facile two-steps approach was employed to synthesize the rGO/TiO2 which involved partial reduction of graphene oxide followed by vacuum thermal treatment. The properties of rGO/TiO2 photocatalysts were thoroughly investigated using SEM, XRD, FTIR, XPS, Raman, PL, N2 adsorption/desorption, and UV-vis spectroscopy. The performance of photocatalysts was evaluated for the reduction of CO2 with H2O using a continuous gas phase fixed bed photoreactor. The highest amounts of methane (CH4) and carbon monoxide (CO) were 12.75 and 11.93 μmol g-1 h-1 over 0.4 wt.% rGO/TiO2 that were 4 fold greater compared to anatase TiO2. Improved photocatalytic activity was attributed to interfacial chemical bonding (Ti-O-C), efficient transfer of electrons, enhanced light absorption and higher adsorption of CO2 due to rGO. Thus, this development could provide an efficient approach to improve the interfacial bonding in graphene based nanocomposites for photocatalytic applications.