Tertiary Amine-Assisted\nElectroreduction of Carbon\nDioxide to Formate Catalyzed by Iron Tetraphenylporphyrin

Abstract

The reduction of CO₂ by electrogenerated Fe(0)­TPP\ncan\nbe directed toward formate with a good selectivity (ca. 70%) upon\naddition of a tertiary amine in the presence of a weak proton donor.\nWhereas most systems generating formate from CO₂ involve\nthe initial formation of a hydride, we demonstrate herein that the\nhydride pathway is avoided by preferential binding of CO₂ that may then be protonated by weak acids. The net result is that\nhydrogen production via the hydride is disfavored, thus leading to\nhigh yields of formate. These results demonstrate an alternative route\nfor the activation of CO₂ to formate.