IR and XPS investigation of visible-light photocatalysis—Nitrogen–carbon-doped TiO2 film

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 N2 gas and then were calcined at 500 8C. 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 bandgap narrowing and photocatalytic activity