Characterization and Reactivity of Alumina-Supported Pd Catalysts for the Room-Temperature Hydrodechlorination of Chlorobenzene

A series of alumina-supported Pd catalysts were prepared by varying the metal loading between 0.5 and 5 wt. %, adopting the deposition precipitation (DP) method. These catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (TPR), pulse CO chemisorption, Brunauer−Emmett−Teller specific surface area measurement, and transmission electron microscopy. The catalytic properties of the catalysts were studied for the hydrodechlorination of chlorobenzene. The reaction was carried out in a continuous mode passing liquid chlorobenzene and gaseous hydrogen over a fixed bed of catalyst taken in a reactor operating at room temperature and atmospheric pressure. The catalysts with metal loading up to 2 wt. % demonstrated high dispersion, homogeneous distribution of active species with predominance of metal−support interaction and without any formation of β-PdH. Beyond 2 wt. % loading, the agglomeration of PdO took place forming bulk particles that reduc...