Naphthalene hydrogenation over Pt/TiO2–ZrO2 and the behavior of strong metal–support interaction (SMSI)

Vapor-phase naphthalene hydrogenation over various supported Pt catalysts was studied in a continuous fixed-bed microreactor. Experimental results indicated that the catalytic activity of the catalyst strongly depended on the nature of the support and the pre-reduction temperature. Reaction order was independent of the support as the reaction was pseudo-first-order with respect to naphthalene in the temperature range studied. By comparing the apparent rate constant over various supported Pt catalysts, Pt supported on TiO2–ZrO2 (1 : 1) reduced at a low temperature showed the highest activity. For higher pre-reduction temperatures, Pt/TiO2–ZrO2 (1 : 1) exhibited the least suppression of H2 uptake, due to a stabilization effect exerted by ZrO2, which prevents the migration of TiOx moieties and the blockage of the Pt surface. However, the apparent depression of the hydrogenation activity of high-temperature reduced Pt/TiO2–ZrO2 (1 : 1) was significantly greater than the suppression of its hydrogen uptake. Furthermore, the decreasing value of the hydrogenation activity relative to the hydrogen uptake demonstrates electron perturbations between the support and the Pt metal. © 2000 Elsevier Science B.V. All rights reserved.