Boosting PEMWE Performance Via the Local Electronic Regulation of Ir0.5Ru0.5/NbN Catalyst With Synergistic Vacancy and a Doping Engineering Strategy.

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 Ir0.5Ru0.5 nanocluster supported on the nitrogen-vacation-rich niobium nitride (Ir0.5Ru0.5/NbN) for acidic oxygen evolution reaction (OER). Through defect engineering, the electron cloud density of Ir0.5Ru0.5 active sites is precisely modulated, thereby reinforcing strong metal-support interaction (SMSI) at interfaces. Concomitantly, Ir0.5Ru0.5 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 Ir0.5Ru0.5/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.