Photo-induced direct interfacial charge transfer at TiO 2 modified with hexacyanoferrate(iii).

Photo-induced electron-transfer reactions occurring at the interface between titanium dioxide modified with hexacyanoferrate(iii) (Fe(iii)-CN-TiO2) were characterized. After the modification of TiO2 with [Fe(CN)6]3- ions, a new absorption appeared in the visible light region (410 to 700 nm). Absorption spectroscopy measurements showed that Fe(iii)-CN-TiO2 was converted to Fe(ii)-CN-TiO2 under visible light irradiation (>520 nm), which indicates that the new absorption was assignable to direct charge transfer from the valence band to the modified Fe(iii) ions.