Engineering Co–O–Ru Motifs in RuO 2 Nanosheets via Asymmetric Spin Polarization for High‐Performance and Durable PEM Water Electrolysis

ABSTRACT The intrinsic activity‐stability trade‐off of RuO 2 remains a fundamental bottleneck, impeding its long‐term viability in acidic oxygen evolution reaction (OER) and large‐scale proton exchange membrane water electrolyzer (PEMWE) deployment. While spin‐polarization modulation has emerged as a compelling paradigm for catalyst optimization, establishing rigorous atomic‐scale structure‐activity correlations remains elusive. Herein, we strategically incorporate isolated cobalt atoms into the RuO 2 lattice (Co 1 ‑RuO 2 ) to engineer Co–O–Ru motifs that trigger asymmetric spin polarization at the Ru sites. Consequently, the Co 1 ‑RuO 2 catalyst delivers a low overpotential of 192 mV at 10 mA cm −2 and sustains exceptional stability for over 200 h with a decay rate of 7 µV h – 1 , outperforming both RuO 2 and commercial benchmarks. Notably, when integrated as a PEMWE anode, the cell sustains 500 mA cm −2 at 1.61 V for over 150 h. This work underscores that asymmetric spin engineering via atomic‐scale coordination provides a potent strategy for transcending traditional catalytic limits, offering a universal blueprint for the rational design of high‐performance electrocatalysts.