Electrocatalytic Activity of PtRu Alloy Colloids for CO and CO/H₂ Electrooxidation: Stripping Voltammetry and Rotating Disk Measurements

Abstract

The electrocatalytic activity of a bimetallic Pt0.5Ru0.5N(Oct4)Cl colloid toward the oxidation of CO and a CO/H2 gas mixture (simulated reformer gas) was measured. The particle size distribution with a mean diameter of 1.7 ± 0.5 nm was determined by high-resolution transmission electron microscopy, and the formation of stoichiometrically alloyed particles was verified by point-resolved energy dispersive X-ray analysis. The CO-stripping voltammetry of glassy carbon supported Pt0.5Ru0.5 clusters was found to be in excellent agreement with CO-stripping voltammetry data measured on well-characterized bulk alloy electrodes. The activity of the colloid toward the continuous oxidation of 2% CO in H2 was assessed in a rotating disk electrode configuration at 25 °C in 0.5 M H2SO4, leading to the conclusion that PtRu colloids are a promising route toward the preparation of bimetallic high-surface-area fuel cell catalysts.