Key points are not available for this paper at this time.
A small percentage of platinum added to silver/gold alloys that are then electrochemically dealloyed yields an extremely high surface area nanoporous metal, with pore size less than 4 nm, as shown in the figure (scale bar = 5 nm). The presence of surface platinum stabilizes the nanostructure to coarsening in air and electrolyte.
Snyder et al. (2008) studied this question.