Study of graphenic powder and monolayer graphene interaction with TiO2 grown by RF sputtering and atomic layer deposition and effect on the photocatalytic activity under solar light

The interaction of monolayer graphene and graphite nanoplatelets with titanium dioxide was studied by means of X-ray photoelectron (XPS) and micro-Raman spectroscopies. TiO2 was deposited either by RF sputtering onto the nanographite powders or by atomic layer deposition (ALD) onto the monolayer graphene. The influence of the RF power during the sputtering process and the film thickness of the ALD films was investigated, with a focus on the electron properties at the interface between the carbon support and the oxide and the structural modifications of the support. A p-doping of graphene was evidenced by XPS as well as by Raman analysis which also revealed strain occurrence in such TiO2-coated nanocarbons. Nanographite- and graphene- supported-TiO2 showed a significant improvement of the photocatalytic activity of TiO2 towards methylene red molecule degradation under UV-Vis light, such an effect being more important for the monolayer graphene-supported TiO2.