• • The ripening-induced embedding strategy yields an OER catalyst with an overpotential of 245 mV at 10 mA cm−2 in 1 M KOH, outperforming commercial IrO2 (typically >300 mV) and reducing energy losses by ~18% in electrolysis.
• • The catalyst sustains 1000 hours of continuous operation at 100 mA cm−2 with negligible degradation, a 50-fold improvement in durability over conventional supported catalysts, which typically fail within 20 hours under similar conditions.
• • In a PEM electrolyzer, the catalyst achieves a cell voltage of 1.72 V at 1 A cm−2 with a decay rate of only 0.12 mV h−1 over 500 hours, meeting the U.S. Department of Energy's 2025 target of <0.13 mV h−1 for system durability.
• • The embedded architecture preserves an electrochemically active surface area of 85 m² g−1, which is 2.5 times higher than that of non-embedded catalysts, ensuring high mass activity (1500 A g−1 at 1.6 V vs. RHE) and reduced noble metal loading by 40%.