Nanoporous foam fabricated by dealloying AgAl thin film through supercritical fluid corrosion.

In this research, nanoporous silver foams are fabricated through dealloying Ag 35 Al 65 (as atomic percentage, at%) thin films in supercritical (SC) carbon dioxide. The supercritical CO 2 is mixed with either HCl, water or H 2 C 2 O 4 aqueous solution as the solute in the reaction chamber. Due to the low tension of the supercritical fluid, under the best operating conditions, the surface area of the as-dealloyed Ag 35 Al 65 can reach 4.6 m 2 g -1 , and the porosity volume fraction value can reach 74%, with a smallest average pore size of around 75 nm. In an optimum supercritical CO 2 environment, a lower chemical concentration can be applied and it can take less time to form a uniform nanoporous structure.