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

ABSTRACT 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 Co ₃ O ₄ 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 Co ₃ O ₄ 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 .