Boosting PEMWE Performance Via the Local Electronic Regulation of Ir _0.5 Ru _0.5 /NbN Catalyst With Synergistic Vacancy and a Doping Engineering Strategy

ABSTRACT Proton exchange membrane water electrolysis (PEMWE) is an environmentally friendly and efficient technology for hydrogen production, playing a vital role in mitigating the fossil energy crisis and bridging renewable energy generation with hydrogen utilization. This work investigates an Ir 0.5 Ru 0.5 nanocluster supported on the nitrogen‐vacation‐rich niobium nitride (Ir 0.5 Ru 0.5 /NbN) for acidic oxygen evolution reaction (OER). Through defect engineering, the electron cloud density of Ir 0.5 Ru 0.5 active sites is precisely modulated, thereby reinforcing strong metal‐support interaction (SMSI) at interfaces. Concomitantly, Ir 0.5 Ru 0.5 nanoclusters with high‐density grain boundaries induce local charge rearrangement and orbital hybridization for precise d ‐band center downshift, are fabricated via a doping strategy, thereby accelerating the intrinsic reaction kinetics of OER. The Ir 0.5 Ru 0.5 /NbN catalyst exhibits excellent OER performance, achieving a low overpotential of 228 mV at 10 mA cm −2 and high stability, maintaining activity for 700 h without degradation. In addition, it presents outstanding performance as an anode in PEMWE with a cell voltage of 1.79 V at 2 A cm −2 . This work provides a viable and efficient approach to reduce Ir loading in PEMWE dramatically, offering a prospective strategy for the cost‐effective generation of green hydrogen.