Enantioselective Synthesis of Amino Acids by Photocatalytic Reduction of CO2 on Chiral Mesostructured ZnS

Abstract The diverse products resulting from CO2 reduction and fixation via solar energy in natural systems spans from small molecules to biomolecules. So far, only a few multicarbon species have been obtained by artificial CO2 photoreduction1-5, especially abiotic photosynthesis of biomolecules with various functional groups has long been a fundamental yet challenging issue. Herein, we report the photocatalytic synthesis of amino acids from CO2 and NH3 on a chiral mesostructured ZnS (CMZ) nanosphere constructed by arrays of chiral nanorods. Serine (Ser), with an enantiomeric excess (ee) greater than 96% is the main component of various amino acids with a total yield of over 30 μmol gcat -1. The experimental data showed that C-C coupling allows the reaction access to the Ser formation pathway through *OCCO intermediates. Chiral induced spin polarization of CMZ has been speculated to facilitate the separation of photogenerated carriers and production of stable triplet OCCO. Different activation energies of reduction reactions driven by the spin-polarized electrons in CMZ would lead to the formation of enantiomeric amino acids. Our findings would inspire new perspectives in catalytic theory and the formation of chiral biomolecules in both artificial synthesis and nature.