Balancing the activity–stability trade-off via catalyst–support interface lattice oxygen sharing for acidic OER

Balancing activity-stability trade-off in acidic oxygen evolution reaction (OER) electrocatalysts remains a central challenge for scalable proton exchange membrane water electrolyzers (PEMWEs). Here, we report a IrO x /Ni-CoO electrocatalyst with ultrasmall IrO x nanoparticles uniformly anchored onto Ni-doped CoO nanowires that exhibits exceptional activity and stability for acidic OER, with overpotential of 248.0 mV at 10 mA cm −2 , and a mass activity of 2271.9 mA mg Ir -1 at 1.53 V vs. RHE, representing a 1081.9-fold enhancement over commercial IrO 2 . When deployed in a PEMWE device, it achieves 1 A cm −2 at 1.73 V and maintains stable operation 750 h, demonstrating promising practical applicability. Comprehensive in situ spectroscopy and density functional theory (DFT) calculations reveal that the lattice oxygen in the Ni-CoO support is involved for the formation of *OO intermediates. This catalyst-support lattice oxygen sharing not only breaks the inherent linear scaling relationship to form reactive O-O coupling for OER but also avoids the formation of oxygen vacancies in IrO x catalysts, thereby mitigating active-site degradation. This study presents a strategy for the development of high-performance and stable acidic OER electrocatalysts that harmonize activity, stability and precious metal utilization.