Mesoporous metal oxide microsphere electrode compositions and their methods of making
Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions include microspheres with an average diameter between about 200 nanometers and about 10 micrometers and mesopores on the surface and interior of the microspheres. The methods of making include forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least annealing in a reducing atmosphere, doping with an aliovalent element, and coating with a coating composition.
1. A method of making a treated mesoporous metal oxide microsphere composition comprising:
forming a mesoporous metal oxide microsphere composition having: (a) microspheres with an average diameter between 200 nm and 10 μm, and (b) mesopores on the surface and interior of the microspheres, wherein the mesopores have an average diameter between 1 nm and 50 nm and the microspheres have a surface area between 50 m 2 /g and 500 m 2 /g;
treating the mesoporous metal oxide microspheres by doping with chromium and nitrogen; and optionally
treating the mesoporous metal oxide microspheres by at least one method selected from the group consisting of: (i) annealing in a reducing atmosphere and (ii) coating with a coating composition.
2. The method of claim 1 , wherein the metal oxide comprises at least one polymorph of titanium dioxide having at least 50 wt. % of a TiO 2 anatase polymorph or at least 50 wt. % of a TiO 2 -B polymorph.
3. The method of claim 1 , comprising annealing the mesoporous metal oxide microspheres in the reducing atmosphere, and the reducing atmosphere is selected from the group consisting of: hydrogen, argon, nitrogen, carbon dioxide, and mixtures thereof.
4. The method of claim 1 , wherein the doping comprises the addition of between 2 mol. % and 5 mol. % of the chromium and nitrogen to the mesoporous metal oxide microspheres.
5. The method of claim 1 , comprising coating the mesoporous metal oxide microspheres with the coating composition, and the coating composition is selected from the group consisting of nitrides, oxides, carbides, halides, borides, phosphides, and combinations thereof.