Photocatalytically active support with TiO2 based materials

A method for producing a photocatalyst support at least micrometric in size and photocatalytically active at least in the visible range, containing nanocrystals each composed of from 80 to 100 mol % of TiO2 and from 0 to 20 mol % of at least one other metal or semi-metallic oxide,

• comprising the following steps that are performed without using a surfactant:
• a1) preparing and heating an acidic aqueous solution to a pH between 0 and 6, and to a temperature between 20° C. and 60° C., with no surfactant, by adding hydrochloric acid,
• a2) adding a titanium oxide precursor, or a mixture of a titanium oxide precursor and of at least one other precursor of another metal or semi-metallic oxide, to the acidic aqueous solution to form a precipitate in the acidic aqueous reaction medium, wherein the precipitate comprises from 80 to 100 mol % of TiO2 and from 0 to 20 mol % of another oxide, and wherein the titanium oxide precursor is a titanium alkoxide,
• a3) agitating the acidic aqueous reaction medium so as to dissolve the precipitate formed in step a2),
• a4) reacting the precursors obtained in step a3) with a support to condense the precursors to the surface of the support and thereby attach the precursors to the surface of the support by covalent bonds, wherein the precursors are attached by:
• spraying the precursor aqueous reaction medium on the support or
• immersing the support in the precursor aqueous reaction medium for a specific time period,
• a5) heating the mixture obtained in step a4) at a temperature between 40° C. and 95° C., wherein the support is at least micrometric in size, making it possible to crystallize the titanium oxide precursors, or the mixture of the titanium oxide precursor and the at least one other precursor of another metal or semi-metallic oxide, on the surface of the support without using a surfactant in the acidic aqueous reaction medium, wherein the precursors crystallize once attached to the surface of the support,
• a6) rinsing in water and recovering the support on which the crystallization took place, wherein nanocrystals are formed as a result of the crystallization and wherein the nanocrystals are composed of from 80 to 100 mol % of TiO2 and from 0 to 20 mol % of at least one other metal or semi-metallic oxide and the nanocrystals are attached to the support by covalent bonds, wherein recovering the support also produces a residual solution.