Enhancement of photocatalytic properties of nanosized La2Ti2O7 synthesized by glycine-assisted sol-gel route

Nanosized lanthanum titanate (La2Ti2O7) have been synthetized by a new glycine-assisted sol gel route in order to improve the photocatalytic properties. The effect of calcination temperature on crystallites size and their photocatalytic efficiency has been investigated, showing a best efficiency for a calcination temperature of 1000 degrees C. Thus, the apparent rate constant of degradation of rhodamine B is greatly improved by a factor of 1.86 compared to commercial P25 TiO2 Degussa (R) and by a factor of 6.42 compared to a sol-gel synthesis without glycine. In order to study the efficiency of the photocatalyst on industrial water discharges, the photodegradation of phenol has also been investigated, showing the effectiveness of the photocatalyst with an apparent rate constant of 5.49 x 10(-3) min(-1). The photocatalyst mass loading, the luminous flux received and the pH have been also investigated. The effect of different type of scavengers shows the importance of superoxide and hole in the photodegradation mechanisms. Finally, the coupling of ultrasound and light excitation was carried out in order to achieve a sonophotocatalysis effect. The apparent rate constant corresponding to the photodegradation of phenol increases slightly. Nevertheless, we have been able to observe that this is more important as the volume of the photoreactor is low.

Automated summary

Nanosized lanthanum titanate synthesized by a glycine-assisted sol gel route shows improved photocatalytic properties. The optimum calcination temperature of 1000 degrees C results in the best efficiency. The photocatalyst exhibits higher degradation rate of rhodamine B compared to commercial P25 TiO2 and sol-gel synthesis without glycine. Photodegradation of phenol also demonstrates the effectiveness of the photocatalyst with a high apparent rate constant.