Figure 5

Illustration of the evolution of the nanoporous Ag-Cu@Ag core-shell alloy. (a) The as-prepared Zr-Cu-Ag-Al-O ribbon. (b) The dissolution of Zr, Al and their oxides. (c) The formation of nanoporous structures with high Cu and Ag content. (d) The cracks form in the nanoporous structures when the dealloying depth reaches a critical value. (e) The dissolution of Zr, Al and the copper oxides, and the redeposition of Cu ions. (f) The formation of Cu network supported nanoporous Ag-Cu@Ag core-shell alloy.