Effects of Palladium Precursors on the Activity and Stability of Pd Catalysts for the Oxidation of Volatile Organic Components (VOCs)

Abstract

Abstract To screen a suitable precursor, the effects of palladium salts on performance of Pd catalysts for the oxidation of volatile organic components (VOCs) were investigated. A series of catalysts were prepared by impregnating different palladium salts on alumina-coated cordierite. These catalysts were characterized by XRF, ICP, XRD, N2 adsorption-desorption, TEM, EDS Mapping, Raman spectroscopy, pulse-CO chemisorption, H2-TPR, NH3-TPD and XPS. Pulse-CO chemisorption and TEM showed that Pd species formed by Pd(NO3)2 have the highest metal dispersion, while the other two are aggregating. H2-TPR and XPS results showed that the catalyst prepared by Pd(NO3)2 has the most active sites. The catalytic oxidation activities of these catalysts were evaluated by ethane and propane. And the catalyst performed the best activity for ethane and propane was prepared by Pd(NO3)2. The chloride species in precursors can promote the aggregation of Pd species and poison the catalysts. The results show that Pd(NO3)2 is more suitable as the precursor of VOCs catalytic oxidation catalyst than PdCl2 and Pd(NH3)4Cl2.