Study of the photocatalytic activity of Fe3+, Cr3+, La3+ and Eu3+ single-doped and co-doped TiO2 catalysts produced by aqueous sol-gel processing

The activity of different TiO2 single-doped and co-doped catalysts has been estimated by the mean normalized 4-NP conversion with standard deviation reached after 7 h under illumination and compared to the TiO2-undoped catalyst.89