Electrocatalytic Transformation of Carbon Dioxide into Low Carbon Compounds on Conducting Polymers Derived from Multimetallic Porphyrins.

The electrochemical reduction of carbon dioxide is studied herein by using conducting polymers based on metallotetraruthenated porphyrins (MTRPs). The polymers on glassy carbon electrodes were obtained by electropolymerization processes of the monomeric MTRP. The linear sweep voltammetry technique resulted in polymeric films that showed electrocatalytic activity toward carbon dioxide reduction with an onset potential of -0.70 V. The reduction products obtained were hydrogen, formic acid, formaldehyde, and methanol, with a tendency for a high production of methanol with a maximum value of turnover frequency equal to 15.07 when using a zinc(II) polymeric surface. Studies of the morphology (AFM) and electrochemical impedance spectroscopy results provide an adequate background to explain that the electrochemical reduction is governed by the roughness of the polymer, for which the possible mechanism involves a series of one-electron reduction reactions.