Ultrastable Y support was obtained by steam dealumination. Double noble metal catalyst with a total loading of Pd and Pt 0.8 wt% was prepared by an ion-exchange method. The supports and catalysts were characterized by temperature programmed desorption of ammonia, X-ray diffractograms, and nitrogen adsorption-desorption isotherms. The activity for the hydrogenation of tetralin, anthracene and pyrene was examined with a stirred tank reactor operating at 6.0 MPa and 250 ℃. It was shown that the catalyst promoted deep hydrogenation of polycyclic arenes. Competitive hydrogenation was also examined. For the naphthalene and anthracene, with the same kinetic diameters, hydrogenation activity of the latter was higher than that of the former. In addition, a strong inhibition exists in this reaction system. The results showed that polycyclic arenes inhibited the hydrogenation of arenes with less number of aromatic rings. While for naphthalene and pyrene with different kinetic diameters, the hydrogenation activity of naphthalene was higher than that of pyrene, indicating that another important factor existed besides the number of aromatic rings.

Key words: noble metal catalyst, steam dealumination, polycyclic aromatics, competitive hydrogenation