Study of Graphenic Carbon Powder Interaction with Tio2 Grown by Rf Sputtering and Effect on the Photocatalytic Activity

Abstract

TiO2 nanoparticles were deposited by RF sputtering onto powders made of graphenic carbon flakes. The influence of the RF power during the sputtering process was investigated, with a focus on the interaction of this powder with titanium dioxide. i.e. the electron properties change at the interface between the carbon support and the oxide and the structural modifications of the support. X-ray photoelectron spectroscopy was employed for such a purpose. It was found that the C 1s core level binding energy in the graphenic powder shifted to lower binding energies values upon the deposition of the TiO2 nanoparticles. Such a downshift was observed on Ti2p and O1s core levels too and increased with rising of TiO2 amount. The downshift of the C 1s core level indicates a charge transfer from graphene to TiO2 nanoparticles due to the lower work function of carbon relatively to that of TiO2, with a lowering of the Fermi level. The graphenic powder - supported TiO2 nanoparticles showed an improvement of the photocatalytic activity towards methyl red molecule degradation under solar light.