Synthesis of PtCu/C Nanostructured Electrocatalysts for the Oxygen Reduction Reaction via One-Step Electrochemical Erosion

Abstract

Reducing the precious metal loading while increasing the oxygen reduction reaction (ORR) mass activity of novel electrocatalysts constitutes one of the remaining key challenges in the widespread application of proton exchange membrane fuel cells, which is inevitable for the transition to the climate-neutral hydrogen economy. However, this requires a simple, scalable, and affordable production of active nanostructured electrocatalysts. Alloyed nanoparticles of Platinum (Pt) with transition metals like cobalt, nickel, or copper have shown promising activity toward ORR, but their preparation usually involves complex multistep processes and environmentally harmful surfactants or structure-capping agents. In this work, we present the successful synthesis of nonspherical copper-alloyed Pt nanoparticles (PtCu) by employing a simple one-step top-down approach without surfactants or capping agents. The electrocatalysts were characterized by high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and inductively coupled plasma mass spectrometry. The ORR kinetics were evaluated using the rotating (ring) disk electrode technique. The synthesized PtCu/C catalysts revealed outstanding mass activities of similar to 1.2 A mgPt -1 at 0.9 V vs the reversible hydrogen electrode, which clearly surpasses state-of-the-art Pt-based catalysts in the literature and demonstrates the highest ORR mass activities reported for PtCu nanoparticles.