Pd/Hβ-zeolite catalysts for catalytic combustion of toluene: Effect of SiO2/Al2O3 ratio

The effect of pure and high silica H beta zeolites on the catalytic performance of toluene combustion over Pd/H beta catalyst was evaluated. Pure and high silica beta zeolites were prepared by direct synthesis procedures, then 0.1 wt% of palladium was impregnated on different H beta zeolites via incipient wetness technique using palladium nitrate as the Pd source. The Pd/H beta catalysts were characterized by XRD, N-2 adsorption/desorption, H2O adsorption, NH3-TPD, H-2-TPR and XPS techniques. With increasing the SiO2/Al2O3 ratio of beta zeolite, the activity of the Pd/H beta catalysts for toluene combustion increased clearly and the pure silica beta zeolite supported Pd catalyst showed the best catalytic activity. The superior catalytic performance of Pd/beta catalyst prepared from pure silica beta zeolite was attributed to its high hydrophobicity and the preserving ability for PdO active species.