METHOD OF PRODUCING A THERMOSTABLE MICROPOROUS COATING BASED ON MIXED TITANIUM-SILICON OXIDE Russian patent published in 2020 - IPC C01G23/04 B01J21/06 B01J35/04 B01J35/10 B01J37/03 B01J37/06 B01J37/08 B82B3/00 B82Y30/00 B82Y40/00 

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of producing a photocatalytically active thermally stable microporous coating based on mixed titanium-silicon oxide on solid substrates. Method comprises applying a single liquid silicon-titanium precursor on the surface of a pre-treated silicate glass with subsequent post-synthetic treatment of the coating, wherein to obtain a silicon-titanium precursor in aqueous solution of titanyl sulphate with concentration of 0.15 mol/l and temperature of not less than 50°C, ammonia aqueous solution is slowly introduced until pH is set to not lower than 10, and obtained hydrated colloidal titanium oxide in form of a precipitate, which is washed with large amount of distilled water to negative reaction to ions of SO₄²⁺ and NH₄⁺, then to the washed hydrated titanium dioxide precipitate slowly while cooling in an ice bath and thoroughly stirring is added aqueous solution of hydrogen peroxide with concentration of not less than 30 % and a solution of the titanium peroxo complex is obtained, adjusting the pH of the solution of the titanium peroxo complex to 9.5 by adding a dropwise aqueous solution of ammonia, diluting it with distilled water to a concentration of titanium atoms equal to 0.05 mol/l, then separately preparing solution of tetraethoxysilane in n-propanol with concentration of 0.05 mol/l, volume of which is equal to volume of solution of peroxocomplex, in which defatted plates of porous borosilicate glass are placed, solution of titanium peroxo complex is poured into solution of tetraethoxysilane with plates of porous borosilicate glass placed in it, wherein the mixed silicon-titanium oxide sol is formed, the plates are held in a precursor for at least 24 hours, removed with the coating formed thereon, dried in a vacuum at temperature not higher than 50 °C, followed by post-synthetic treatment of coating, at which dried plates are poured with a mixture of water-ethanol, 1:1 by volume, at a pH value equal to 5, obtained by adding hydrochloric acid to the mixture, then performing plates refluxing for at least 21 hours, after which the plates are removed, dried under vacuum at temperature not higher than 50 °C and subjected to annealing in muffle furnace at temperature of 700 °C for not less than two hours. Formed on solid substrates microporous coating of mixed titanium-silicon oxide synthesized from inexpensive and low-toxic compounds formed on solid substrates (titanyl sulphate, water solutions of ammonia and hydrogen peroxide, tetraethoxysilane), high content (not less than 95 %) of the anatase phase and high photocatalytic activity under high (up to 1000 °C) temperatures.

EFFECT: technical result consists in obtaining a chemically, thermally and mechanically stable coating based on highly porous and photocatalytically active anatase stabilized in a silicon oxide matrix.

1 cl, 4 dwg, 1 ex