Preparation of the Pd/La_0.8Ce_0.2MnO₃/ZSM-5 catalyst and its performance in catalytic combustion of toluene

Pd/La_0.8Ce_0.2MnO₃/ZSM-5 catalysts were prepared by incipient wetness impregnation and characterized by nitrogen physical adsorption, X-ray diffraction (XRD), scanning electron microscope (SEM), and temperature-programmed reduction (H₂-TPR). The catalytic combustion of toluene as a target pollutant over the Pd/La_0.8Ce_0.2MnO₃/ZSM-5 catalysts was investigated in a fixed-bed reactor and the effect of calcination temperature, active component loading and ZSM-5 properties on the catalytic performance was investigated. The results indicated that the Pd/La_0.8Ce_0.2MnO₃/ZSM-5 preserves the perovskite structure and the active Pd component is evenly dispersed on the catalyst surface, which endures the catalyst with high activity in toluene combustion. Over the La_0.8Ce_0.2MnO₃/ZSM-5 catalyst with La_0.8Ce_0.2MnO₃ loading of 20%, ZSM-5 Si/Al atomic ratio of 25, and calcination temperature of 750℃, the ignition and complete combustion temperatures for toluene combustion are only 200 and 279℃, respectively. After being modified with 0.3% Pd, the activity of the Pd/La_0.8Ce_0.2MnO₃/ZSM-5 catalyst is even largely enhanced; over it, the ignition temperature for toluene combustion is decreased by 90℃ and complete combustion is achieved at 230℃.