Co-sputtered carbon-incorporated titanium oxide films as visible light-induced photocatalysts

Carbon-incorporated titanium oxide (TiOxCy) films in anatase structure were deposited by co-sputtering titanium and graphite targets in argon and oxygen. The incorporation of carbon into TiO2 retained the crystallinity of anatase phase and the carbon is a mix of both graphitic as well as substitutional in nature. The microstructure of the TiOxCy films consisted of columnar carbon-doped titania grains covered with graphitic carbon along the grain boundaries. The films exhibited absorption bands in the visible light region with an absorption edge red-shifted up to ∼ 450 nm corresponding to a band gap ∼ 2.7 eV and while absorption tails continued to above 700 nm. The films possessed outstanding visible light-induced photocatalytic properties in the reduction of silver ions, degradation of methylene blue and superhydrophilicity.