Spin‐Polarized Interfaces Redirect CO ₂ Reduction From CO to Formate

ABSTRACT

Achieving high product selectivity in electrocatalytic carbon dioxide reduction (CO ₂ RR) remains a critical challenge due to competition between multiple proton‐coupled electron‐transfer pathways on catalyst surfaces. Meanwhile, chirality‐induced spin selectivity (CISS), which enables spin‐polarized electron transport through chiral interfaces, has recently emerged as a promising strategy to modulate interfacial electrochemical reactions. Although the CISS effect has been shown to enhance selectivity and efficiency in the spin‐sensitive oxygen evolution reaction (OER), its role in regulating CO ₂ RR pathways and in stabilizing intermediates remains largely unexplored. Here, chiral molecules (R‐ and S‐1,1′‐bi‐2‐naphthyl‐2,2′‐diyl hydrogen phosphate, BNP) were integrated with SnO ₂ to construct chiral‐modified catalysts (R‐BNP/SnO ₂ and S‐BNP/SnO ₂ ). Compared with bare SnO ₂ and racemic BNP‐modified SnO ₂ (Rac‐BNP/SnO ₂ ), the chiral catalysts exhibited a pronounced shift in product selectivity from CO toward formate production. Importantly, in‐situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS) reveals that the chiral interface selectively stabilizes the O‐bound *OCHO intermediate associated with the formate pathway and modulates interfacial water structure and hydrogen‐bonding dynamics. These findings demonstrate that spin‐polarized interfacial electron transfer can regulate CO ₂ RR pathway selectivity by modulating the stabilization of key intermediates. More broadly, this work establishes chiral spin‐selective interfaces as a new strategy for regulating competitive electrocatalytic reaction pathways.