Improving the Efficiency and Activity of Electrocatalysts for the Reduction of CO₂ through Supramolecular Assembly with Amino Acid-Modified Ligands

Abstract

The use of hydrogen-bonding interactions to direct the noncovalent assembly of a Re-based bimetallic supramolecular electrocatalyst containing either tyrosine or phenylalanine residues is reported. Computational modeling and spectroelectrochemical characterization indicate that under catalytic conditions the phenol residues of tyrosine can act both as pendant proton sources and participate in the structural assembly of the bimetallic active species. As a result, an increased rate of catalysis is observed experimentally for the reductive disproportionation of CO2 to CO and CO3(2-) by a tyrosine-modified complex in comparison to a control complex containing phenylalanine residues. These findings demonstrate that noncovalent assembly is a powerful method for generating new bimetallic electrocatalyst systems where the choice of substituent can be used to both control structural assembly and introduce cocatalytic moieties.