Controlling the Polarity of Metal-Organic Frameworks to Promote Electrochemical CO 2 Reduction

The addition of polar functional groups to porous structures is an effective strategy for increasing the ability of metal-organic frameworks (MOFs) to capture CO by enhancing interactions between the dipoles of the polar functional groups and the quadrupoles of CO . However, the potential of MOFs with polar functional groups to activate CO has not been investigated in the context of CO electrolysis. In this study, we report a mixed-ligand strategy to incorporate various functional groups in the MOFs. We found that substituents with strong polarity led to increased catalytic performance of electrochemical CO reduction for these polarized MOFs. Both experimental and theoretical evidence indicates that the presence of polar functional groups induces a charge redistribution in the micropores of MOFs. We have shown that higher electron densities of sp -carbon atoms in benzimidazolate ligands reduces the energy barrier to generate *COOH, which is simultaneously controlled by the mass transfer of CO . Our research offers an effective method of disrupting local electron neutrality in the pores of electrocatalysts/supports to activate CO under electrochemical conditions.