Ultra-Pure Nanoporous Gold Films for Electrocatalysis

Nanoporousgold (Au) films are self-supported structures that possessa large surface area and extraordinary catalytic activity. Generally,nanoporous gold is obtained by solution-based dealloying where theless noble metal, often silver (Ag), is etched out. However, the residualamounts of the sacrificial metal are not well controlled, the impuresamples show restructuring, and the residual metal prevents the studyof the catalytic role of Au alone. Here, we fabricate impurity-freenanoporous gold films by a plasma-enabled dry synthetic route. Thescheme does not include sacrificial metals or solution processingand is much more general. It is used to obtain self-supported ultra-purenanoporous gold films with controllable pore sizes. The impurity-freenanoporous gold films possess highly curved ligaments, are remarkablyrobust, and stable over hundreds of electrochemical cycles. Furthermore,they contain many catalytically active sites, which is highly promisingfor electrocatalytic applications.