Understanding the Enhancement in Photoelectrochemical Properties of Photocatalytically Prepared TiO2-Reduced Graphene Oxide Composite

Abstract

Solution-phase photocatalytic reduction of graphene oxide to reduced graphene oxide (RGO) by titanium dioxide (TiO 2 ) nanoparticles produces an RGO-TiO 2 composite that possesses enhanced charge transport properties beyond those of pure TiO 2 nanoparticle films. These composite films exhibit electron lifetimes up to four times longer than that of intrinsic TiO 2 films due to RGO acting as a highly conducting intraparticle charge transport network within the film. The intrinsic UV-active charge generation (photocurrent) of pure TiO 2 was enhanced by a factor of 10 by incorporating RGO; we attribute this to both the highly conductive nature of the RGO and to improved charge collection facilitated by the intimate contact between RGO and the TiO 2, uniquely afforded by the solution-phase photocatalytic reduction method. Integrating RGO into nanoparticle films using this technique should improve the performance of photovoltaic devices that utilize nanoparticle films, such as dye-sensitized and quantum-dot-sensitized solar cells.