Porous materials via freeze-casting of metal salt solutions
Disclosed here is a method for making a nanoporous material, comprising aerosolizing a solution comprising at least one metal salt and at least one solvent to obtain an aerosol, freezing the aerosol to obtain a frozen aerosol, and drying the frozen aerosol to obtain a nanoporous metal compound material. Further, the nanoporous metal compound material can be reduced to obtain a nanoporous metal material.
1. A method for making a nanoporous metal material, comprising:
aerosolizing a solution comprising at least one metal salt and at least one solvent to obtain an aerosol;
freezing the aerosol to obtain a frozen aerosol;
drying the frozen aerosol to obtain a nanoporous metal compound material; and
converting the nanoporous metal compound material to a nanoporous metal material, wherein the nanoporous metal material comprises at least about 40 wt. % of elemental metal.
2. The method of claim 1 , further comprising assembling the nanoporous metal material into a macroscopic monolith.
3. The method of claim 1 , wherein the solution comprising a silver salt and/or a copper salt.
4. The method of claim 1 , wherein the solution comprising at least two metal salts.
5. The method of claim 1 , wherein the solution comprising water as the solvent.
6. The method of claim 1 , wherein the solution is aerosolized by a nebulizer, a nozzle, a syringe, and/or a sprayer.
7. The method of claim 1 , wherein the aerosol has an average or mean droplet diameter of 100 microns or less.
8. The method of claim 1 , wherein the aerosol is frozen by contact with liquid nitrogen.
9. The method of claim 1 , wherein the frozen aerosol is dried in a vacuum chamber.
10. The method of claim 1 , wherein the frozen aerosol is dried at a temperature of about −90° C. to about 25° C.
11. The method of claim 1 , wherein the nanoporous metal compound material is reduced by thermal or gas treatment.
12. The method of claim 1 , wherein the nanoporous metal compound material is reduced thermally at a temperature of about 600° C. or less.
13. The method of claim 1 , wherein the nanoporous metal compound material is reduced by light.
14. The method of claim 1 , wherein the nanoporous metal material obtained comprises at least about 80 wt. % of elemental metal.
15. The method of claim 1 , wherein the nanoporous metal material obtained has a porosity of at least about 30%.
16. The method of claim 1 , wherein the nanoporous metal material obtained has a porosity of at least about 50%.
17. The method of claim 1 , wherein the nanoporous metal material obtained has a density of about 1000 mg/cc or less.
18. The method of claim 1 , wherein the nanoporous metal material obtained has a density of about 100 mg/cc or less.