Synthesis, Characterization, and Electrocatalytic Activity of PtBi Nanoparticles Prepared by the Polyol Process

Polycrystalline networks of nanoparticles of the ordered intermetallic phase of PtBi have been prepared at 160 °C using the polyol process. In this reaction the polyol acts as both the solvent and the reducing agent. Powder X-ray diffraction (pXRD) studies confirm the presence of the ordered intermetallic phase with an average grain size of ∼19 nm. Electron microscopy studies show that these grains are agglomerated in open networks. pXRD and scanning electron microscopy (SEM) show that the reaction proceeds through an intermediate phase and that the morphology of the particles changes during the course of the reaction. The products have been characterized by SEM, STEM, EDX, CBED, and EELS. The surface area of the nanoparticles has also been measured via BET using krypton as the adsorbing gas. The electrocatalytic activity of the PtBi intermetallic phase towards the oxidation of formic acid has been studied by cyclic voltammetry. The as-prepared PtBi nanoparticles exhibited enhanced electrocatalytic activity when compared to that of Pt nanoparticles and PtRu nanoparticles in terms of both oxidation onset potential and current density.