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

In this research, nanoporous silver foams are fabricated through dealloying AgAl (as atomic percentage, at%) thin films in supercritical (SC) carbon dioxide. The supercritical CO is mixed with either HCl, water or HCO 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 AgAl can reach 4.6 m g, and the porosity volume fraction value can reach 74%, with a smallest average pore size of around 75 nm. In an optimum supercritical CO environment, a lower chemical concentration can be applied and it can take less time to form a uniform nanoporous structure.