Stacked cone carbon nanotubes (SC-CNT) with a BET surface area of similar to 280 m(2)/g were used as the support medium to prepare Pt catalysts for partial dehydrogenation of tetralin and decalin to produce pure hydrogen and naphthalene. The results show that for dehydrogenation of tetralin at 240 degrees C, 1.0 wt % Pt/SC-CNT is more active than 1.0 wt % Pt catalyst supported on granular carbon or carbon black ( acetylene soot) and more active than 1.0 wt % Pt, Pd, or Rh supported on gamma-alumina. HRTEM characterization of the used catalysts established that Pt was more highly dispersed on SC-CNT than on the other supports. At 240 degrees C, dehydrogenation of decalin produces hydrogen, tetralin, and naphthalene. The small amount of tetralin present in the products compared with the amount of naphthalene produced suggests that the dehydrogenation of decalin to tetralin is slower than the dehydrogenation of tetralin. cis-Decalin exhibits a higher conversion rate than trans-decalin, suggesting that the flexible geometric structure of cis-decalin makes it easier to be adsorbed on the catalyst surface.