Synthesis and characterization of La2Ti2O7 employed for photocatalytic degradation of reactive red 22 dyestuff in aqueous solution

Perovskite structured La2Ti2O7 catalyst prepared by polymerized complex method was characterized and examined the photocatalytic activity by decomposing an azo dyestuff, Reactive Red 22, in aqueous solutions under UV irradiation. La2Ti2O7 powders prepared by polymerized complex method exhibit higher surface areas, better homogeneity and are more sensitive to solution than those prepared by solid-state method. The first derivatives of UV-vis DRS patterns confirmed the complete crystallization of La2Ti2O7 sintered at temperatures higher than 900 degrees C. The effects of sintering temperature of catalyst and solution pH of photocatalytic reaction were studied. The photocatalytic decomposition of Reactive Red 22 per unit surface area was found to be higher for experiments using La2Ti2O7 than using TiO2. However, the electron-hole recombination was found to be more obvious for La2Ti2O7 than for TiO2 because the network of metal cations constructed within La2Ti2O7 enhances the mobility of photogenerated electrons and holes. (C) 2011 Elsevier B. V. All rights reserved.