New mixed PtMo catalysts supported on Zr-doped mesoporous silica have been prepared by using a polynuclear organometallic complex as precursor of the active phase, and tested in the catalytic hydrogenation of tetralin at high hydrogen pressure. The PtMo catalysts have been characterized by XRD, TEM, XPS, N-2 sorption at 77 K, H-2-TPR and NH3-TPD. In order to evaluate the influence of the precursor, a PtMo catalyst has been also prepared from inorganic monometallic salts. The PtMo catalysts were very active in the hydrogenation of tetralin, showing conversion values close to 100%, and high selectivity toward the hydrogenation products (trans- and cis-decalins). The trans- to cis-decalin ratio varies depending on the type of precursor used. The formation of hydrogenolysis, isomerization and cracking products depends on the acidity of the catalysts, although the selectivity towards these products is always lower than 8.5%. On the other hand, all the studied catalysts showed a poor thiotolerance against the presence of dibenzothiophene in the feed. (c) 2006 Elsevier B.V. All rights reserved.