Spin-Polarized Chiral ZnIn₂S₄ for Targeted Solar-Driven CO₂ Reduction to Acetic Acid

Acetic acid represents a pivotal target for CO₂ reduction due to its dual function as a carbon-utilization product and industrial feedstock. However, photocatalytic CO₂ reduction (PCCR) to acetic acid typically suffers from low acetic acid yields and selectivity, constrained by competing reactions from ethanol and inefficient C-C coupling. Herein, we report a chiral mesostructured ZnIn₂S₄ (CMZI) photocatalyst that achieves a remarkable acetic acid yield of 962 µmol g^-1 h^-1 with a high selectivity of 97.3%. This performance stems from synergistic chirality-induced spin polarization and sulfur site catalysis. Spin polarization stabilizes the triplet OCCO intermediate to enhance C-C coupling, while sulfur sites on ZnIn₂S₄ {102} facets thermodynamically and kinetically favor acetic acid formation. This work offers critical insights into catalytic strategies of the efficient synthesis of high-value multicarbon products and expanding the variety of synthetic products from CO₂ reduction.