To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Nitrogen and carbon doping TiO2-x-yNxCy films were obtained by heating the TiO2 gel in an ionized N-2 gas and then were calcined at 500 degrees C. The TiO2-x-yNxCy films have revealed an improvement over the TiO2 films under visible light (wavelength, 500 nm) in optical absorption and photocatalytic activity such as photodegradation of methyl orange. X-ray photoemission spectroscopy, infrared spectrum and UV-visible (UV-vis) spectroscopy were used to find the difference of two kinds of films. Nitrogen and carbon doped into substitutional sites of TiO2 has been proven to be indispensable for band-gap narrowing and photocatalytic activity. (c) 2006 Elsevier B.V. All rights reserved.