Photocatalytic properties of nano-structured TiO2-carbon films obtained by means of electrophoretic deposition

Recent studies have shown that the light-absorption and photocatalytic efficiencies of TiO2 can be improved by coupling TiO2 nano-particles with nonmetallic dopants, such as carbon. In this paper, we describe the electrophoretic preparation of a novel TiO2-carbon nano-composite photocatalyst on a glass indium thin oxide (ITO) substrate. The objective is to take better advantage of the (e−/h+) pair generated by photoexcitation of semiconducting TiO2 particles. The transfer of electrons (e−) into adjacent carbon nano-particles promotes reduction of oxygen to produce hydrogen peroxide (H2O2) which, in the presence of iron ions, can subsequently form hydroxyl radicals (OH) via the Fenton reaction. At the same time, OH is formed from water by the (h+) holes in the TiO2. Thus, the OH oxidant is produced by two routes. The efficiency of this photolytic-Fenton process was tested with a model organic compound, Orange-II (OG-II) azo dye, which is employed in the textile industry.