A catalyzed fabric filter substrate and a method of preparing the substrate comprising the steps of a) providing a fabric filter substrate b) providing an aqueous impregnation liquid comprising an aqueous hydrosol of one or more catalyst metal precursor compounds dispersed on nanoparticles of an oxidic metal carrier, a surfactant and a dispersing agent selected from the group of primary amines; c) impregnating the fabric filter substrate with the impregnation liquid; and d) drying and thermal activating the impregnated fabric filter substrate at a temperature below 300° C. to convert the one or more metal compounds of the catalyst precursor to their catalytically active form.