Microstructures of nanoporous gold films

Cyanide-free gold plating introducing Na3Au(SO3)2 as the gold compound is employed to prepare gold films by electroless plating and pulsed electroplating. The gold films are coated on an anodic aluminum oxide template, which is then dissolved in nitric acid solution. Scanning electron microscopy and X-ray diffraction analyses show that the gold films prepared by both methods present a porous structure. However, the difference in their microstructures is evident: the sample prepared by electroless plating possesses a dendritic structure, and that prepared by electroplating consists of nanowires.