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

The effect of pure and high silica Hβ zeolites on the catalytic performance of toluene combustion over Pd/Hβ catalyst was evaluated. Pure and high silica β zeolites were prepared by direct synthesis procedures, then 0.1 wt% of palladium was impregnated on different Hβ zeolites via incipient wetness technique using palladium nitrate as the Pd source. The Pd/Hβ catalysts were characterized by XRD, N2 adsorption/desorption, H2O adsorption, NH3-TPD, H2-TPR and XPS techniques. With increasing the SiO2/Al2O3 ratio of β zeolite, the activity of the Pd/Hβ catalysts for toluene combustion increased clearly and the pure silica β zeolite supported Pd catalyst showed the best catalytic activity. The superior catalytic performance of Pd/β catalyst prepared from pure silica β zeolite was attributed to its high hydrophobicity and the preserving ability for PdO active species.