Characterization of a TiO2 photocatalyst synthesized by the solvothermal method and its catalytic performance for CHCl3 decomposition

Abstract

It is considered that the solvothermal method in this study renders a reliable synthesis procedure of the TiO2 photocatalyst having the anatase structure of nano size. Two kinds of TiO2 photocatalysts were synthesized by using the sol–gel and solvothermal methods, and then their physical properties and catalytic performances were compared. The TiO2 powder (Cat. 2) obtained by the solvothermal method at 300°C exhibited a pure anatase structure without any further treatment, while the TiO2 powder (Cat. 1) prepared by the sol–gel method was transformed to the anatase structure after thermal treatment at 500°C for 3h. Cat. 2 had higher surface area (121m2/g) and surface charge (+24.1mV) than Cat. 1 (51m2/g, +16.4mV). In addition, the activation energy for H2O desorption over Cat. 2 was very high. These results show that the surface of Cat. 2 is very hydrophilic. In chloroform (CHCl3) decomposition under the UV-light (254nm, 24W/m2) with O2 bubbling (500ml/min), the catalytic performance of Cat. 2 was considerably higher than that of Cat. 1. More than 95% of the chloroform was decomposed in 2h over Cat. 2.