Diffusion-Enhanced Hierarchically Macro-Mesoporous Catalyst for Selective Hydrogenation of Pyrolysis Gasoline

摘要

A novel Pd/Al2O3 catalyst with the hierarchically macro-mesoporous structure was prepared and applied to the selective hydrogenation of pyrolysis gasoline. The alumina support possessed a unique structure of hierarchical mesopores and macropores. The as-prepared and calcined alumina were characterized by X-ray diffraction, N2 adsorp-tion-desorption, and scanning electron microscopy. It showed that the hierarchically porous structure of the alumina was well preserved after calcination at 1073 K, indicating high thermal stability. The 1073 K calcined alumina was impregnated with palladium metal and compared with a commercial catalyst without macrochannels. Both the catalytic activity and the hydrogenation selectivity of the novel Pd/Al2O3 catalyst were higher than those of the commercial PdlAl2O3 catalyst. In addition, apparent reaction activation energies obtained with the novel catalyst for model pyrolysis gasoline were 46-81% higher than those with the commercial catalyst. The results adequately demonstrated the enhanced mass transfer characteristics of the novel macro-mesostructured catalyst.