Ultrastable and Phosphoric Acid-Resistant PtRhCu@Pt Oxygen Reduction Electrocatalyst for High-Temperature Polymer Electrolyte Fuel Cells

With much enhanced fuel flexibility to overcome the shortcomings of hydrogen production and storage, high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) are still facing challenges of activity loss of oxygen reduction electrocatalyst under the working circumstance of phosphoric acid (PA) electrolyte. Dissolution and leaching of metal component of PtM (M = Cu, Co, Ni) electrocatalysts is one of the key factors that degrade their initial resistance toward PA and hinder the accessing of activity and durability simultaneously. Here, we report an ultradurable PtRhCu@Pt/C electrocatalyst with a high mass activity of 0.90 A mg(Pt)(-1), which only decreased by 14.4% after 30K ADT cycles in the half-cell and reaches the DOE at 2025 target (<30 mV at 0.8 A cm(-2)) with 27 mV voltage loss at 0.8 A cm(-2) in the single-cell. After adding 0.1 M PA into the electrolyte, the half-wave potential of PtRhCu@Pt/C is negatively shifted by only 52 mV, much lower than that of commercial Pt/C (90 mV). Moreover, the HT-PEMFC assembled by this catalyst delivers a preeminent peak power density of 529 and 977 mW cm(-2) under H-2-air and H-2-O-2 conditions, respectively. Experiments and theoretical calculations reveal that the ligand effect arising from the sublayer Cu is attributed to the ability of PA resistance, while the self-healing behavior and the synergy between the PtRhCu core and the Pt shell ensures high stability.