Impact of Pt-Ni Nanoparticle Architecture on Electrocatalytic Oxidation Reaction in Fuel Cells

This paper investigates how the aggregation of bimetallic nanoparticles (NPs) influences the electronic condition of the surface adsorption site and, hence, the performance of materials during the electrooxidation of fuels in an alkaline medium. First, we synthesized Pt-Ni NPs in three configurations: ordered intermetallic, ordinary alloy, and core-shell. The NPs contained Pt and Ni close to a 1:1 Pt/Ni atomic ratio. They had similar particle sizes, which allowed us to evaluate their performance without the influence of these physical parameters. Depending on the structural arrangement of the Pt and Ni atoms in the NP, the electronic condition of the surface adsorption site (Pt) changed significantly. Consequently, the performance of the materials varied whenever they were used as anode material for the electrooxidation of hydrogen, methanol, ethanol, ethylene glycol, and glycerol in an alkaline solution. The electronic condition of the surface site strongly affected the adsorption characteristics of the reactants, intermediates, and products, consequently impacting the material's performance during the electrochemical processes. The approach adopted here could contribute to a better understanding of electrocatalytic processes and the design of selective electrocatalysts.