Corrosion‐Inspired Stabilization of Cobalt Oxide Catalysts via Platinum‐Mediated Redox Buffering for Proton Exchange Membrane Water Electrolysis

Proton exchange membrane water electrolysis (PEMWE) is considered a promising platform for sustainable hydrogen production at scale. However, the durability of anode catalysts under acidic and oxidative conditions remains a critical challenge. Cobalt-based oxides offer an attractive alternative to iridium-based catalysts due to their abundance and cost-effectiveness, yet suffer from severe chemical and structural degradation during the acidic oxygen evolution reaction (OER). In this study, we report a corrosion-inspired stabilization strategy based on platinum (Pt)-mediated redox buffering. Platinum, incorporated within the Co₃O₄ spinel lattice, functions as a redox-active buffer, preferentially undergoing oxidation during OER to divert oxidative stress away from the cobalt matrix. In situ X-ray absorption spectroscopy, inductively coupled plasma-mass spectrometry analyses, and isotope-labeled differential electrochemical mass spectrometry collectively demonstrate that Pt incorporation suppresses cobalt dissolution and minimizes lattice oxygen participation, preserving the spinel framework under acidic OER conditions. The resulting Pt-incorporated Co₃O₄ catalyst demonstrates outstanding PEMWE performance, achieving a current density exceeding 2500 mA cm^-2 at 2.0 V with a turnover frequency of 0.376 s^-1, and maintains stable operation for over 1000 h at 250 mA cm^-2.