Photocatalytic properties of fresh and pyrolyzed transparent nanocomposite films layer-by-layer fabricated from alternative layers of graphene and titanate nanotube

Abstract

Aiming at the efficient utilization of light absorption and controlled contacting of graphene and titania nanoparticles, layer-by-layer (LbL) technique was employed to fabricate composite films of nanosized thickness with alternative layers of graphene oxide and titanate nanotube and the fabrication processes were monitored by the surface charge changes of substrates. By appropriately choosing synthesis conditions, it is possible to build up uniform multicomponent films which are transparent from visible through UV (lower to 200nm) wavelengths up to ≈8 bilayers. The photocatalytic activity of the fresh and pyrolyzed composite films was found dependent on the bilayer number, the reactant concentration, and the pyrolysis temperature. Photodecomposition rate of methyl orange together with mineralization rate by the composite films was enhanced by about two folds at the maximum as compared to the pure titania film. The results demonstrated that thickness control by LbL technique followed by post pyrolysis is an important approach to obtain uniform hybrid films with robustness, transparency, and the close contacting of graphene and titania for achieving enhanced photocatalysis at a small amount of TiO2.