Chemical process for preparing a solution suitable for deposition of photocatalytic coatings

摘要

A precursor of titanium is mixed with water and a basic catalyst to undergo hydrolysis and polycondensation. The ratio of titanium precursor to catalyst favors submicronic crystalline growth. The resulting mixture is diluted by an organic solvent with a boiling point above water or minimal azeotrope with water and then reconcentrated by eliminating the water or the water-solvent azeotrope The catalyst used is a basic catalyst which does not deteriorate the photo-catalytic properties of the anatase crystals. ALSO CLAIMED is a process for obtaining a self-cleaning substrate which has a coating with photocatalytic properties on at least part of one face based on partially crystallized titanium dioxide incorporated in the form of anatase. This coating is obtained using a deposit of solution as described above. The solution is treated at a temperature at or below 140 deg. C. ALSO CLAIMED is a self-cleaning substrate as described above obtained using the above process.