VOx-TiO2 catalysts with vanadium loading less than that of a monolayer have been prepared either by impregnation in aqueous media from solutions of V(V) or V(IV) at different concentrations and pH, or by grafting in anhydrous media on anatase supports with surface areas of 10, 150 and 350 m(2) g(-1). Their characterisation by XPS, DRIFT and Raman spectroscopy, compared to that of EUROCAT EL10V1 and V8 reference catalysts, shows that the dispersion of the load depends on the mode of preparation and is not necessarily equal to 1.