Enhanced Activity and Stability of a Carbon-Coated Alumina-Supported Pd Catalyst in the Dehydrogenation of a Liquid Organic Hydrogen Carrier, Perhydro 2-(n-methylbenzyl)Pyridine

The activity and stability of supported Pd catalysts are of crucial importance in the dehydrogenation of perhydro 2-(n-methylbenzyl)pyridine (H-12-MBP) reported as a potential liquid organic hydrogen carrier. Because of good stability examined in many hydroprocessing reactions, carbon-coated alumina (CCA) was chosen as a support for Pd loading and prepared by the pyrolysis of glycerol solution with different concentrations. The catalytic activity and stability of Pd/CCA catalysts exhibited a volcano-shaped relationship with the carbon content. Various characterization results revealed that the degree of carbon coating affected the acidity, Pd loading and particle size, reactant adsorption capacity, and H-2 release at low temperatures. At an optimal carbon content (3.3wt% in this work), these properties are believed to be balanced well, thus showing the best catalytic performance. Moreover, the improvement of catalytic activity was examined with supported Pd on carbon-coated silica-alumina of 3.3wt% carbon content.