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

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.