One-Step Electrosynthesis of Bimetallic Au-Pt Nanoparticles on Indium Tin Oxide Electrodes: Effect of the Deposition Parameters

Bimetallic Au-Pt nanoparticles (Au-Pt(NPs)) were prepared by one-step electrochemical reduction of KAuBr(4) and K(2)PtCl(4) precursors in acidic media. Characterization of Au-Pt(NPs) was made by scanning electron microscopy, X-ray diffraction, UV-vis spectroscopy, and cyclic voltammetry. The effects of gold and platinum precursors molar ratio and the deposition time were studied, Pt and Au nanoparticles (Pt(NPs) and Au(NPs)) were also electrosynthesized for comparison. The results show that the bimetallic system can be obtained only with 1:1 or 2:1 Au/Pt molar ratio; all the other ratios afford the electrosynthesis of Pt(NPs) and Au(NPs) in separate domains. The deposition time seems to affect preliminarily the percentage of surface coverage and not the composition of the nanoparticles. The electrocatalytic behavior of bimetallic Au-Pt(NPs) catalyst for methanol oxidation was investigated in alkaline conditions; the results show a higher catalytic efficiency for Au(70)Pt(30) composition.