Dinuclear Metal Synergistic Catalysis Boosts Photochemical CO 2 ‐to‐CO Conversion

The solar‐driven CO 2 reduction is a challenge in the field of “artificial photosynthesis”, as most catalysts display low activity and selectivity for CO 2 reduction in water‐containing reaction systems as a result of competitive proton reduction. Herein, we report a dinuclear heterometallic complex, [CoZn(OH)L 1 ](ClO 4 ) 3 (CoZn), which shows extremely high photocatalytic activity and selectivity for CO 2 reduction in water/acetonitrile solution. It achieves a selectivity of 98 % for CO 2 ‐to‐CO conversion, with TON and TOF values of 65000 and 1.8 s −1 , respectively, 4, 19, and 45‐fold higher than the values of corresponding dinuclear homometallic [CoCo(OH)L 1 ](ClO 4 ) 3 (CoCo), [ZnZn(OH)L 1 ](ClO 4 ) 3 (ZnZn), and mononuclear [CoL 2 (CH 3 CN)](ClO 4 ) 2 (Co), respectively, under the same conditions. The increased photocatalytic performance of CoZn is due to the enhanced dinuclear metal synergistic catalysis (DMSC) effect between Zn II and Co II , which dramatically lowers the activation barriers of both transition states of CO 2 reduction.