Boosting photocatalytic CO2-to-CO conversion using a biomimetic dinuclear Co(II) complex through an HCO3−-mediated pathway

Dinuclear metal synergistic catalysis (DMSC) has been evidenced to be effective in enhancing the catalytic activity for CO 2 reduction. However, the reaction kinetics of CO 2 reduction is still limited by the local CO 2 concentration around the dinuclear catalytic centers. Inspired by the structure of carbonic anhydrase, we have designed and synthesized a dinuclear cobalt(II) complex with an –OH group. This complex not only exhibits DMSC for CO 2 reduction but also possesses excellent capture capacity for CO 2 molecules. Consequently, the complex demonstrates high efficiency for the photocatalytic reduction of CO 2 to CO, with turnover number reaching as high as 43,400 and a selectivity of 97%. Even in 10% CO 2 , the complex still shows state-of-the-art catalytic activity. The results of experiments and theoretical calculations reveal that besides the DMSC contributing to the enhanced catalytic activity, the –OH group in the dinuclear cobalt(II) complex facilitates the capture of CO 2 by the formation of HCO 3 − intermediates, thereby enhancing the affinity towards CO 2 and boosting the catalytic activity for CO 2 -to-CO conversion.