Spin-enhanced electrosynthesis of amino acids on oxide-derived chiral bismuth nanohelices

Electrochemical synthesis of amino acids from waste-derived nitrate and biomass-sourced α-keto acids represents a sustainable approach, but its efficiency is fundamentally constrained by hydrogenation steps associated with spin-state reconfiguration during NO ₃ ⁻ to NH ₂ OH conversion. Herein, chiral bismuth oxide nanohelices are prepared through cysteine-induced symmetry breaking and cathodically converted into oxide-derived chiral bismuth nanohelices (CBNs). These CBNs function as highly efficient spin filters, enabling spin-polarized electron transfer that promotes spin-matched hydrogenation pathways. The spin polarization of CBNs aligns the unpaired electron of adsorbed *NO in spin-antiparallel configuration via exchange interactions and facilitates the formation of spin-polarized H species, cooperatively lowering the kinetic barrier for the key *NO + H → *NHO step and accelerating *NH ₂ OH formation. Consequently, L-CBNs achieve a Faradaic efficiency of 81% and a yield rate of 1120 µmol h⁻ ¹ cm⁻ ² for glycine electrosynthesis from NO ₃ ⁻ and glyoxylic acid, surpassing achiral bismuth nanorods (ABNs) and most reported catalysts. The strategy further generalizes the synthesis of multiple amino acids from diverse α-keto acids. Our findings underscore the potential of chiral catalysts to modulate spin-dependent reaction kinetics and indicate that chirality-induced spin polarization is a viable strategy for enhancing amino acid electrosynthesis.