Chae, KyungheeKyungheeChaeLee, HeejunHeejunLeeHuang, Wen‐TseWen‐TseHuangSon, JaehyunJaehyunSonPavageau, BertrandBertrandPavageauKim, Tae‐HyunTae‐HyunKimLee, Seung‐eunSeung‐eunLeeKim, JeongwonJeongwonKimMoon, JoohoJoohoMoonLiu, Ru‐ShiRu‐ShiLiuBang, JoonhoJoonhoBangKim, Dong HaDong HaKim2025-08-222025-08-222025-06-26https://scholars.lib.ntu.edu.tw/handle/123456789/731568Water electrolysis, driven by renewable electricity, offers a sustainable path for hydrogen production. However, efficient bifunctional electrocatalysts are needed to overcome the high overpotentials of both the oxygen evolution reaction and hydrogen evolution reaction. To address this, a novel catalyst system is developed integrating plasmonic nanoreactors with chirality-induced spin selectivity. In this system, chiral Au nanoparticles act as antennae, while single-atom iridium serves as the catalytic reactor, achieving a 3.5 fold increase in reaction kinetics (at 1.57 V vs RHE) compared to commercial IrO2 catalysts and enhancing durability by over 4.8 times relative to conventional Pt/C || IrO2 systems. Density functional theory and operando X-ray absorption spectroscopy reveal that plasmon-driven spin alignment polarizes the Ir atom, significantly enhancing stability (>480 h at 100 mA cm−2) under acidic conditions. This work represents a major advance in spin polarization for plasmonic electrocatalysis, offering a new route to sustainable energy solutions.enCISS effectplasmonic effectsingle atom catalysisstabilitywater splitting[SDGs]SDG3[SDGs]SDG7[SDGs]SDG12journal article10.1002/adma.202507658