Abstract: The present invention concerns a method for the preparation of a metal oxide catalyst comprising of molybdenum (Mo), vanadium (V), tellurium (Te), and niobium (Nb) and having a modified surface structure, comprising the steps of (i) providing a calcined catalyst material comprising oxides of Mo, V, Te, and Nb, (ii) treating agent selected from water and an aqueous solution of an acid or a base. (iii) separating the treated catalyst from the treating agent; and further a catalyst, obtainable by this process, and the use of this catalyst in oxidation reactions of hydrocarbons or partially oxidized hydrocarbons.