TiOx, VOx and TiOx-Vo(x) oxides were highly dispersed at different metal loadings on the mesoporous silica SBA-15 by the molecular designed dispersion (MDD) method. A combination of different techniques (N,_-sorption, FT-Raman, TPR, UV-vis-DR) was used to verify the nature of the vanadia and/or titania species on the surface of the mesoporous support. Temperature-programmed desorption (NH3-TPD) was applied to characterise the surface acidity of these catalysts. Vanadia and titania were found to be present as isolated species, even at high metal oxide concentrations. The supported catalysts were tested in the selective catalytic reduction (SCR) of NO with ammonia. Among the studied samples, the highest activity was found for TiOx-VOx mixed oxides on SBA-15. The catalytic activity results were discussed in terms of loading and metal dispersion on the support material. (c) 2005 Elsevier B.V. All rights reserved.