The Response of TiO[sub 2] Photocatalysts Codoped with Nitrogen and Carbon to Visible Light

We successfully achieved deposition of Ti͑O,C,N͒ 2 films codoped with nitrogen ͑N͒ and carbon ͑C͒ using dc reactive sputtering utilizing a Ti target in an Ar/N 2 /CO 2 ambient.The crystallinity and surface morphology of the films were observed using X-ray diffraction ͑XRD͒ and field-effect scanning electron microscopy.Interstitial N and C in the films were also measured using X-ray photoelectron spectroscopy ͑XPS͒, from which the doping level was calculated.The photocatalytic activity was evaluated using methylene blue decomposition under visible and ultraviolet irradiation.All the films were transparent yellow, and it was confirmed using XRD that the crystal form was polycrystalline anatase.Two peaks resulting from Ti-N bonding ͑397 eV͒ and Ti-C bonding ͑282 eV͒ were observed using XPS.Thus, N and C were considered to be at substitutional O sites.It was verified that the Ti͑O,C,N͒ 2 films deposited in this study undergo a photocatalystic reaction when exposed to visible light in the wavelength range of 400-500 nm.