Synthesis and characterization of Zr4+, La3+ and Ce3+ doped mesoporous TiO2: Evaluation of their photocatalytic activity

Sol-gel method was used to synthesize Zr4+, La3+ and Ce3+ doped mesoporous TiO2 materials with different weight percentage (0.5, 1.0, 2.0 and 3.0 wt%) using triblock copolymer as the structure directing template in ethanol/water medium. Characterization revealed the isomorphic substitution of Zr4+ ion into the lattice of TiO2, and surface binding nature of La3+ and Ce3+ ions on mesoporous TiO2. Microscopic examination confirmed the surface adsorption of foreign ion which could alter the particle morphology. The size of the particles was less than 20 nm. Photocatalytic activity of metal ions doped mesoporous TiO2 was evaluated using aqueous alachlor as a model pollutant. It was found that 1 wt% Ce3+ doped mesoporous TiO2 exhibited higher activity than pure and other metal ions doped mesoporous TiO2. The change of oxidation state of Ce3+ is suggested to be the cause for enhanced photocatalytic activity.