Catalytic hydrogenation of ethylanthraquinone over highly dispersed eggshell Pd/SiO2–Al2O3 spherical catalysts Original Research Article

Spherical Al2O3 and SiO2–Al2O3 supports with different silica contents have been synthesized by the oil column method. After impregnation with Na2PdCl4 solution and subsequent calcination, PdO/Al2O3 and PdO/SiO2–Al2O3 catalyst precursors were obtained. X-ray powder diffraction and low temperature N2 adsorption–desorption measurements showed that the addition of silica increased the thermal stability, surface acidity, specific surface area and total pore volume of the spherical alumina. Temperature programmed reduction and H2–O2 titration indicated that Pd supported on the SiO2–Al2O3 spheres possessed higher dispersion and smaller particle size than that supported on pristine spherical Al2O3. Catalytic hydrogenation of ethylanthraquinone using molecular hydrogen was studied over the reduced Pd/Al2O3 and Pd/SiO2–Al2O3 catalysts with different silica contents. Under identical reaction conditions, the reaction activity and stability increased with increasing silica content.