Nanoporous Gold Foams with Tunable Porosity Fabricated by Chemical Dealloying

S. Niauzorau, A. Sharstniou, M. Gregory, B. Azeredo
Arizona State University,
United States

Keywords: nanoporous gold, dealloying, porosity, volume fraction

Summary:

Recently, porous materials and, particularly, porous metal powders and foams fabricated by various techniques, such as dealloying, electrochemical and electroless deposition, templating, sputtering, have drawn a growing interest as they can be implemented in fields such as energy storage, chemical catalysis, bio- and chemical sensing, and medicine. Moreover, nanoporous metal thin-films and foams exhibit unique properties that vary from bulk material properties. In this paper, we show a study on the porosity dependence of dealloyed gold-silver films fabricated by chemical dealloying in the varying acid concentration and etching time. By controlling the acid concentration, it was possible to tune the nanoporous silver-gold morphology from partially to a completely dealloyed films with pore sizes from 5 to 40 nm. The capability of tuning the dealloying conditions gives a high level of control of the porous gold morphology (size of pores and pore volume fraction).