Structure Dependence of CO2 Reduction Electrocatalyzed by Metal-Nanographene Complexes: A Computational Study.

Abstract

Improving the energy efficiency of electrocatalytic reduction of CO2 requires tuning of redox properties of electrocatalysts to match redox potentials of the substrate. Recently, we introduced nanographenes as ligands for metal complexes for such purposes by taking advantage of size-dependent properties of the conjugated systems. Here, we use computations to investigate the structure dependence of the electrocatalysis at Re(diimine)(CO)3Cl complexes with nanographene ligands that contain a polycyclic aromatic hydrocarbon moiety through a pyrazinyl linkage. We show that the reduction potentials of the complexes depend not only on conjugation size but also on shape and geometry of the ligands, revealing another parameter in tuning the redox properties of the electrocatalysts. In addition, our work reveals a compromise between reduction potentials and activation of this class of electrocatalysts.