Synthesis of nanoporous copper by dealloying of Al-Cu-Mg amorphous alloys in acidic solution: The effect of nickel

Dealloying of Al-Cu-Mg based amorphous alloys in 1 M HCl solution and the effect of a minor amount of Ni in the precursor alloy were explored. A crystalline, Cu-rich, nanoporous structure with a pore diameter of 10–30 nm was formed as a result of the selective dissolution of Al and Mg and the reorganization of the remaining Cu. The entire specimen was fully dealloyed after prolonged exposure to a HCl solution. The nanoporous structure is finer (e.g. 10 nm) in the alloy containing Ni, likely because Ni suppresses the surface diffusion of Cu. The decrease in surface diffusion, in turn, suppresses the coarsening of the ligaments in the dealloyed layer enabling tunable porosity development. Electrochemical reactivity after the synthesis of nanoporous Cu was enhanced by a factor of 150 with Ni and 50 without Ni compared to a planar Cu electrode of the same overall dimensions.