Effect of Ce, N and S multi-doping on the photocatalytic activity of TiO2

A visible light active photocatalyst was synthesized by multiple doping of TiO2 with Ce, N and S. The multidoped catalyst showed higher photocatalytic activity for methyl orange degradation from aqueous solution compared to P25 and undoped TiO2. The photocatalytic activity decreased in the order Ce0.6NS-TiO2 > P25 > NS-TiO2 > Ce0.6-TiO2 > TiO2. TiO2 and doped TiO2 existed as anatase phase with average particle size of 10 nm. In the multidoped TiO2, N substituted for O whereas S substituted for Ti. UV-vis absorption spectra showed an increased visible light absorption for doped TiO2 compared to the undoped one. An increased fluorescence lifetime for the charge carriers was observed for the doped samples as compared to undoped TiO2. The enhanced photocatalytic activity of Ce0.6NS-TiO2 is attributed to a synergistic effect of the dopants in increasing the visible light absorption and lifetime of the photogenerated charge carriers. (C) 2013 Published by Elsevier B.V.