Atomically Dispersed High-Valent d⁰‑Metal Breaks the Activity–Stability Trade-Off in Proton Exchange Membrane Water Electrolysis

Green hydrogen production via proton exchange membrane water electrolysis (PEMWE) faces economic feasibility challenges, primarily due to its reliance on noble metal catalysts. While cost-effective Ru-based catalysts show promise as alternatives to expensive Ir-based catalysts for an anodic oxygen evolution reaction, their long-term performance is compromised by overoxidation at high current densities. In addressing this challenge, we present a cooperative dual-site strategy for atomic-scale incorporation of high-valent d⁰-metal cations into RuO₂. This synthesis results in uniformly distributed Ru–O–d⁰metal bonds, effectively reconciling the activity and stability trade-off. Leveraging these effects, our optimized Ta₁/RuO₂ catalyst demonstrates exceptional performance, with a low overpotential of 164 ± 2 mV and stable operation for 1000 h at 100 mA cm^–2. In practical PEMWE systems, Ta₁/RuO₂ achieves 1.58 V at 2 A cm^–2, surpassing the 2026 Department of Energy target, and maintains remarkable stability over 650 h at 500 mA cm^–2. This breakthrough offers a highly active and durable PEMWE system suitable for industrial-scale applications.