Nitrogen-doped titanium dioxide photocatalysts for visible response prepared by using organic compounds
Yoshio Nosaka, Masami Matsushita, Junichi Nishino and Atsuko Y. Nosaka
Department of Chemistry, Nagaoka University of Technology, Kamitomioka, Nagaoka, Niigata 940-2188, Japan
Received 31 August 2004; revised 4 October 2004; accepted 10 November 2004. Available online 22 February 2005.
In order to utilize visible light in photocatalytic reactions, nitrogen atoms were doped in commercially available photocatalytic TiO2 powders by using an organic compound such as urea and guanidine. Analysis by X-ray photoelectron spectroscopy (XPS) indicated that N atoms were incorporated into two different sites of the bulk phase of TiO2. A significant shift of the absorption edge to a lower energy and a higher absorption in the visible light region were observed. These N-doped TiO2 powders exhibited photocatalytic activity for the decomposition of 2-propanol in aqueous solution under visible light irradiation. The photocatalytic activity increased with the decrease of doped N atoms in O site, while decreased with decrease of the other sites. Degradation of photocatalytic activity based on the release of nitrogen atoms was observed for the reaction in the aqueous suspension system.
Keywords: Photocatalyst; Titanium dioxide; Nitrogen doping; Guanidine; Visible light