Mechanism for Visible Light Responses in Anodic Photocurrents at N-Doped TiO2 Film Electrodes

✍ Scribed by Nakamura, Ryuhei; Tanaka, Tomoaki; Nakato, Yoshihiro

• Book ID: 111857925
• Publisher: American Chemical Society
• Year: 2004
• Tongue: English
• Weight: 77 KB
• Volume: 108
• Category: Article
• ISSN: 0022-3654
• DOI: 10.1021/jp048112q

✦ Synopsis

Nitrogen doping of anatase TiO 2 powder extended the photocurrent action spectrum for water oxidation from the UV-light region (e400 nm) to the visible-light region (e ∼550 nm), as reported. Investigations of the effect of the addition of reductants such as methanol, SCN -, Br -, I -, and hydroquinone to the electrolyte have for the first time given clear experimental evidence to the mechanism that visible-light responses for N-doped TiO 2 arise from an N-induced midgap level, formed slightly above the top of the (O-2p) valence band. The investigations, in combination with the above mechanism, have also shown that photocatalytic oxidation of organic compounds on N-doped TiO 2 under visible illumination mainly proceed via reactions with surface intermediates of water oxidation or oxygen reduction, not by direct reactions with holes trapped at the N-induced midgap level.