Fabrication of nanoporous gold film electrodes with ultrahigh surface area and electrochemical activity

Nanoporous gold film (NPGF) electrode was fabricated by applying multicyclic potential scans on a polished gold electrode in an electrolyte composed of ZnCl2 and benzyl alcohol. In the cathodic potential scan, Zn was first electrodeposited on the gold electrode surface, and Au-Zn alloy was then directly formed on the surface under an elevated temperature. In the subsequent anodic potential scan, dealloying of Zn took place, resulting in a nanostructured gold film. Furthermore, Zn was then electrodeposited onto the porous gold surface and a Au-Zn alloy was formed at the same time. Through controlling the parameters of cyclic voltammetry and cyclic times, we finally obtained a three-dimensional NPGF with nanopores. The resulting NPGF possessed ultrahigh roughness factor and surface area. Results showed that the electrochemical activity of the NPGF electrode was much higher than that of the polished gold electrode. We believe that the resulting NPGF electrode is promising in the fields of catalysis, sensors, and so on. Meanwhile, this multicyclic electrochemical alloying/dealloying method may be applied to fabricate other nanoporous metal films.