Effect of Thermal Treatment on the Atomic Structure and Electrochemical Characteristics of Bimetallic PtCu Core–Shell Nanoparticles in PtCu/C Electrocatalysts

Supported PtCu/C electrocatalysts containing core–shell bimetallic PtCu nanoparticles were synthesized by sequential chemical reduction of Cu2+ and Pt­(IV) in a carbon suspension, prepared on the basis of ethylene glycol–water solvent, and then treated at different temperatures in the range from 250 to 350 °C. The structural characterization of “as-prepared” PtCu nanoparticles and of those obtained after the thermal treatments was performed by transmission electron microscopy, X-ray diffraction, and Pt L3- and Cu K-edge extended X-ray absorption fine structure spectroscopy. The atomic cluster models of PtCu nanoparticles before and after the thermal treatment, reflecting the character of the components’ distribution, were generated. The electrochemical performance of the obtained PtCu/C electrocatalysts in oxygen reduction reaction was studied by cycling and linear voltammetry.