New composite materials as support for selective hydrogenation; egg-shell catalysts Original Research Article

It has been demonstrated that using low-cost materials and a relatively simple process, complex supports with a mixed inorganic–organic structure can be synthesized. These supports combine hydrophilic–hydrophobic dual properties and are especially suited for preparing egg-shell supported metal catalysts to be used in highly exothermal catalytic reactions or in systems of consecutive reactions where diffusive problems decrease the selectivity. The synthesized supports have an extremely thin active layer. They also proved to be more mechanically resistant than other commercial supports thus being amenable for use in continuous processes with long packed beds. Pd catalysts supported over the new composite materials were found to be highly active for the selective hydrogenation of styrene, a representative compound of pyrolisis gasolines. They also displayed smaller diffusive constraints than other Pd catalysts prepared from commercial supports.