Hydrodesulfurization of dibenzothiophene over CoMo/HMS and CoMo/Ti-HMS catalysts

Hexagonal mesoporous materials (HMS) with and without titanium were used as supports for preparation of CoMo HDS catalysts. The supports and the catalysts were characterized by adsorption-desorption of nitrogen, XRD, DRS UV-vis, TPR and DRIFTS in the OH region. The catalytic activity of the samples was evaluated in the reaction of hydrodesulfurization of dibenzothiophene. The activity of the CoMo/HMS and CoMo/Ti-HMS catalysts was compared to that of a conventional industrial CoMo/Al2O3 catalyst. The CoMo/ Ti-HMS catalyst demonstrated to be more activate than Ti-free catalysts. The presence of Ti ions into the HMS framework impedes the formation Of Co2SiO4 and Of beta-CoMoO4 inactive phases. It is suggested that the higher activity of the Ti-containing catalysts is related to the better dispersion of the supported CoMo phase, the higher concentration of octahedral Co2+ species, larger pore size diameter and lower reduction-sulfidation temperature of the supported species. (c) 2005 Elsevier B.V. All rights reserved.