Relationship Between Metal Dispersion, Hydrogen Desorption, and Activity for Benzene Hydrogenation Over Pd/SiO2 Catalysts

A series of Pd/SiO2 catalysts with Pd loadings from 1-10wt% were prepared by aqueous hydrazine reduction. They were characterized by XRD, TEM, EDX, H-2 chemisorption, and H-2-TPD. The catalytic performances were evaluated in benzene hydrogenation in the temperature range 100-250 degrees C. The metal dispersion (mean particle size 6.8-28.4nm) and hydrogen reservoir increase with decreasing metal content. The catalytic activity of the Pd/SiO2 catalysts was found influenced by the reaction temperature and metal dispersion. The activity increases with metal dispersion. This might be ascribed to the Pd sites, which increase with the increase of the metal dispersion.