Ionic Pool-Assisted Polyhedron Pt₂FeCo/C Ordered Ternary Alloy as Outstanding Oxygen Reduction Reaction Electrocatalysts

This study aims to enhance the sluggish kinetics of the oxygen reduction reaction at the cathode of polymer electrolyte membrane fuel cells ordered polyhedron (OP) Pt2FeCo ternary alloy electrocatalytic nanoparticles on a high surface area carbon support were prepared in a highly polarized ionic pool (molten) salt condition. The formation of mainly 8 nm OP nanoparticles with a face-centered tetragonal (fct) crystal structure was confirmed by transmission electron microscopy and the presence of superlattice peaks in the X-ray diffraction pattern, respectively. X-ray photoelectron spectroscopy revealed the existence of Pt, Fe, and Co on the surface of the nanoparticles. Furthermore, the electrochemical measurements indicated that the OP Pt2FeCo/C nanoparticles expressed 11- and 17-times higher mass and specific activity, respectively, than commercial Pt/C. Finally, the stability test showed that even after 30,000 potential cycles, 89% of the initial activity of the OP Pt2FeCo/C ternary alloy electrocatalyst was retained, confirming its highly stable nature.