Enhanced activity for catalytic oxidation of 1,2-dichloroethane over Al-substituted LaMnO3 perovskite catalysts

A series of Al-substituted Lai _,AL,Mn03 (x=0 0.3) catalysts were prepared using a sol-gel method and tested for 1,2-dichloroethane oxidation in order to investigate the effects of Al-doping and thermal treatment on the catalyst structures and catalytic behaviors. It was found that both Al-doping and thermal treatment had great influence on the activities of the catalysts, and the highest activity was obtained on a La0.8A10.2Mn03 catalyst calcined at 700 C, with a T50 of 295 C. The enhanced activity could be attributed to synergetic effects of its high surface area, high reducibility and surface acidity, as evidenced by various characterizations such as H2 temperature-programmed reduction and NH3 temperature-programmed desorption. However, comparisons of the areal specific reaction rates revealed that the catalysts calcined at 900 C had much higher rates than the ones calcined at 500 and 700 C, suggesting that structural properties of the catalysts exerted much stronger influence on the catalytic performance than the surface area. It was also evidenced that the reducibility of the catalyst had a dominant role in determining the intrinsic activity, which was closely related to the presence of high valent Mn4-1 species in the catalyst as induced by the introduction of Al in the catalyst. (C) 2014 Elsevier B.V. All rights reserved.