Chelating N‐Heterocyclic Carbene Ligands Enable Tuning of Electrocatalytic CO₂ Reduction to Formate and Carbon Monoxide: Surface Organometallic Chemistry

Reported here is the chelate effect as a design principle for tuning heterogeneous catalysts for electrochemical CO 2 reduction. Palladium functionalized with a chelating tris‐N‐heterocyclic carbene (NHC) ligand (Pd‐timtmb Me ) exhibits a 32‐fold increase in activity for electrochemical reduction of CO 2 to C1 products with high Faradaic efficiency (FE C1 =86 %) compared to the parent unfunctionalized Pd foil (FE=23 %), and with sustained activity relative to a monodentate NHC‐ligated Pd electrode (Pd‐mimtmb Me ). The results highlight the contributions of the chelate effect for tailoring and maintaining reactivity at molecular‐materials interfaces enabled by surface organometallic chemistry.