Transferring enzyme features to molecular CO₂ reduction catalysts

Carbon monoxide dehydrogenases and formate dehydrogenases efficiently catalyze the reduction of CO₂. In both enzymes, CO₂ activation at the metal active site is assisted by proximate amino acids and Fe–S-clusters. Functional features of the enzyme are mimicked in molecular catalysts by redox-active ligands, acidic and charged groups in the ligand periphery, and binuclear scaffolds. These components have all improved the catalytic performance of synthetic systems. Recent studies impart a deeper understanding of the individual contributions of the various functionalities to reactivity and of their combined effects. New catalyst platforms reveal alternate pathways for CO₂ reduction, unique intermediates, and strategies for switching selectivity. Design of a wider array of complexes that combine different functional elements is encouraged to further optimize catalysts for CO₂ reduction, especially for product formation beyond CO. More diverse bimetallic catalysts are needed to better exploit metal–metal interactions for CO₂ conversion.