Abstract: A method for producing agglomerated and activated TiO2 or TiO2/MxOy comprising the steps of: preparing and heating a surfactant-free aqueous solution at neutral pH or at a given acidic pH, adding to the acidic or neutral aqueous solution a titanium oxide precursor, or a mixture of a titanium oxide precursor TiO2 and at least one other precursor of another oxide MxOy, composed of more than 80 mol % of TiO2 and less than 20 mol % of another metal or semi-metal oxide MxOy, and stirring the acidic or neutral aqueous reaction medium; immersing a plastic material or a crushed mixture of plastic materials in the acidic or neutral aqueous reaction medium; heating the acidic or neutral aqueous reaction medium at a temperature of between 30° C. and 90° C.; photocatalytically degrading, at neutral or acidic pH, the plastic material or the mixture of plastic materials to obtain agglomerated and activated TiO2 or TiO2/MxOy.