Catalytic performance of Pd/Ce-based catalyst for oxidation of chlorobenzene

Series of Pd/Al2O3 catalysts were prepared by equal volume impregnation method. The effects of different Pd loadings on the catalytic activity of chlorobenzene were investigated. The results showed that the activity of 0.75% Pd/Al2O3 catalyst was the highest. Based on the purpose of reducing the amount of precious metals by introducing rare earth metal to improve the performance of the catalyst, Ce was introduced into the catalyst of 0.5% Pd/Al2O3, and the optimal ratio of Pd/Ce catalyst was obtained. It was found that the activity was best when the Ce amount was 2.5% by weight. The characterizations of the catalyst by BET, H2-TPR, SEM, etc. confirmed that the oxidation capacity was enhanced and the catalytic oxidation efficiency was improved through the addition of Ce. In addition, the catalytic products were analyzed with ion chromatography and GC-MS. The results showed that a small amount of benzene was formed at 350℃. At the same time, the effects of calcination temperature, chlorobenzene concentration and space velocity on the catalytic activity were investigated. The results showed that the calcination temperature greatly affected the activity of the catalyst. The activity of the catalyst calcined at 550℃ was the best, and the CB conversion was 96% when calcination temperature was 400℃. When the concentration of chlorobenzene was 1500-6000mg/m3, the activity of chlorobenzene decreased with the concentration. When the space velocity was in the range of 15000-30000h-1, it had little effect on the catalytic activity of chlorobenzene. © 2019, Chemical Industry Press. All right reserved.