Yongping Cui, Yuanbo Li, Zhiqiang Wang, Xueliang Zhang, Lu Han, Xueli Wang, Jinquan Chen, Aokun Liu, Yu Lu, Changlin Tian, Xue‐Qing Gong, Wanning Zhang, Yuxi Fang
ABSTRACT Acetic acid represents a pivotal target for CO 2 reduction due to its dual function as a carbon‐utilization product and industrial feedstock. However, photocatalytic CO 2 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 ZnIn 2 S 4 (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 ZnIn 2 S 4 {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 CO 2 reduction.