Preparation of binary metal electrocatalysts by self-assembly of precursor ionic species on gold and reduction of nitrate ions

Pt/Sn binary metal electrodes were prepared by the successive adsorption of Sn2+ and PtCl62− ions onto a gold substrate followed by the reduction of the adsorbed PtCl62−. The atomic ratios of Sn and Pt to the surface Au were determined to be approximately 1 and 0.3, respectively, using a quartz crystal microbalance (QCM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry. Therefore, binary metal layers at a monolayer level were formed. These Pt/Sn binary metal electrodes exhibited a very high electrocatalytic activity for the reduction of nitrate ions with the predominant formation of ammonium ions.