Structural analysis of carbon-supported Ru-decorated Pt nanoparticles synthesized using forced deposition and catalytic performance toward CO, methanol, and ethanol electro-oxidation

Carbon-supported Ru-modified Pt nanoparticles (Ru(Pt)/C), prepared using forced deposition under H2 stream, were tested as anodic fuel cell electrocatalysts. Ru nanoislands, mainly composed of RuO, RuO2, and hydrous RuO2 (RuOxHy), were deposited on the Pt nanoparticles. The coverage of Pt by Ru species (θ) depended on the Ru salt concentration and the treatment duration, the deposition process following an adsorption-controlled Elovich-type kinetics. The CO oxidation kinetics was optimal for θ ≈ 0.50, whereas for both, methanol and ethanol, the highest activity was found for θ ≈ 0.15–0.20. The observed promotional effect was attributed to the reaction of hydroxylated Ru species with strongly adsorbed CO and related intermediates. The forced deposition technique appears to be a suitable simple method for the preparation of Ru(Pt) nanoparticles with improved fuel oxidation performance. The Tafel analysis allowed correlating the reaction pathway and the limiting step with the coverage by Ru.