Oxygen Reduction\nReaction Activity and Stability of\nShaped Metal-Doped PtNi Electrocatalysts Evaluated in Gas Diffusion\nElectrode Half-Cells

The synthesis of bimetallic and trimetallic platinum-based\noctahedral\ncatalysts for the cathode of proton exchange membrane fuel cells (PEMFCs)\nis a particularly active area aimed at meeting technological requirements\nin terms of durability and cost. The electrocatalytic activity and\nstability of these shaped catalysts were tested at relatively high\npotentials (@0.9 V vs RHE) and at lower current densities using the\nrotating disk electrode, which is less suitable for assessing their\nbehavior under the operating conditions of PEMFCs. In this work, we\nuse a gas diffusion electrode (GDE) half-cell setup to test the performance\nof the catalysts under application-oriented conditions, relatively\nhigher current densities, and a square-wave stability test. After\nthe stability test, we analyzed the GDE catalytic layer to study the\nagglomeration and dissolution of the transition metal under these\nconditions by using high-resolution scanning electron microscopy and\nenergy-dispersive X-ray spectroscopy. The present results provide\nvaluable guidance for developing next-generation active and durable\ncatalysts for PEMFCs.