How Stable Are Spherical Platinum Nanoparticles Applied to Fuel Cells

We report on the synthesis, characterization, and degradation behavior of spherical platinum nanoparticles (Pt-NPs). The Pt-NPs were synthesized with and without carbon-support using the “water-in-oil” microemulsion method. X-ray diffraction (XRD) was used to examine their average crystallite size, which was ca. 4.0 nm. The shape, size, and size distribution of the Pt-NPs were evaluated using transmission electron microscopy (TEM); the average size was ca. 4.0 nm, thus in agreement with the XRD data. The agreement between the XRD and TEM data indicates that the Pt-NPs were single crystallites in nature. Thermogravimetric analysis (TGA) measurements were carried out to evaluate the metal loading, which was close to the target value of 40 wt %. Cyclic voltammetry (CV) experiments were performed in 0.50 M aqueous H2SO4 in the s = 1.00–50.0 mV s–1 potential scan rate to determine the specific surface area (As) of the catalysts and to assess the cleanliness of the system. The Pt surface oxide growth and reduct...