Fabrication of uniform nanoparticulate gold through potential-modulated electrochemical deposition and dissolution of silver in ionic liquids

Nanoparticulate gold (NPG) has been successfully produced from polycrystalline Au by a novel method based on potential-modulated electrochemical deposition and dissolution of silver in an ionic liquid bath comprising of 1-ethyl-3-methylimidazolium chloride and silver nitrate at elevated temperatures. Cyclic voltammetric measurements exhibit that the potential cycles between −1.0 and 0.75 V versus a silver pseudo reference electrode can drive the electrochemical deposition and dissolution of silver onto and away from the Au electrode. Scanning electron microscope studies show that the NPG resulting from the potential cycles has very narrow particle size distribution with an average diameter of approximately 50 nm and is free of elemental Ag residue. As compared to a bulk Au electrode, the NPG electrode demonstrates substantially enhanced electrochemical responses. It exhibits a seven-time higher electro-catalytic activity toward the electrooxidation of nitrite in acidic media.