Nanoporous metal (Cu, Ag, Au) films with high surface area: General fabrication and preliminary electrochemical performance

Nanoporous films (NPFs) of copper, silver, and gold were directly fabricated on the corresponding metal substrates by a general alloying/dealloying process. This process involved the electrodeposition of Zn on metal surfaces, thermal alloying, and chemical dealloying of Zn. Electrodeposition of Zn on metal substrates was realized in commercial Zn plating electrolyte at room temperature. Then surface zinc-metal alloys were formed by thermal treatment at relatively low temperatures (below 150 degrees C) in nitrogen gas. By immersing the alloys in etching solutions, we obtained metal NPFs through chemical dissolution of Zn from the alloys. Characterization results showed that the morphologies and porous structures of the products were greatly affected by the thickness of the deposited Zn layer and thermal alloying temperature. Moreover, preliminary testing showed that the as-prepared gold NPF possessed a higher surface area than the polish one. Furthermore, the Au NPF could serve as a nanoporous skeleton for fabricating Pt-coated a Au NPF electrode. The oxidation current of glucose was improved about 180 times when using the resulting Pt-coated Au NPF composite electrode instead of the polished Pt electrode. This study provides a general method to directly fabricate nanoporous metal films on the corresponding metal substrates.