Support effect of Pd/AlPO4 catalyst in hydrogen storage of organic hydride method in the presence of CO

In order to examine the capability of AlPO4 to serve as a catalytic support, we analyzed naphthalene hydrogenation over Pd/AlPO4 catalyst in the presence of CO. This process is an effective storage strategy in the organic hydride method that uses low grade hydrogen. Pd/AlPO4 demonstrated high activity in naphthalene hydrogenation similar to Pd/SiO2-Al2O3, and retained the activity in much higher extent in the presence of CO as compared to Pd/Al2O3. The existence of acidic sites on the surface of AlPO4 was confirmed by ammonia adsorption. FTIR analysis of adsorbed CO after high temperature evacuation revealed that CO desorbed more easily on Pd surface when supported on acidic materials. Detailed analysis of the IR spectra suggested that acidic support decreased the electronic density of Pd and weakened the adsorption bond. Because CO retardation decreased on acidic supports, Pd catalysts demonstrated high activity in the presence of CO. We found that AlPO4 was an effective acidic support for Pd catalyzed hydrogenation.