Molybdenum catalysts supported on titania and zirconia have been prepared via the impregnation on the corresponding hydroxides and oxides. The solids have been characterized by surface area measurements, XR-Fluorescence analysis, XRD and Raman Spectroscopy. The isopropanol decomposition reaction has been used to probe their acidic properties. These analyses revealed that introduction of molybdenum on the surfaces of the hydroxides and the oxides results in an increase of the specific surface area. Impregnation on the hydroxide leads to a comparatively better molybdenum dispersion and to a greater surface acidity. This indicates that the acid sites on hydroxide derived solids are stronger and more numerous than on their oxide derived counterpart. (C) 2016 Elsevier B.V. All rights reserved.