Electrochemical Reduction of CO 2 with a Functional Gas‐Diffusion Electrode in Aqueous Solutions With and Without Propylene Carbonate

Abstract

A functional gas‐diffusion electrode consisting of a modified platinum mesh electrode and a glass filter has been developed in order to convert to a useful substance at an overpotential as low as possible. The modification was made by laminating Prussian blue (inner) and polyaniline (outer) on a Pt mesh substrate, and a metal complex was further immobilized onto polyaniline. The improvement of the usefulness of the product and the required overpotential was brought about by using such functional gas‐diffusion electrode in a KCl aqueous solution containing 10% propylene carbonate. This is attributed to the maintenance of a high concentration of at the electrode surface owing to the direct supply of through the gas phase, the high solubility of to the solution, and the stabilization of reaction intermediates. The maximum total current efficiency for the reduction of was 74.9% at −0.6 V vs. Ag/AgCl, and the main products were ethanol and lactic acid. © 1999 The Electrochemical Society. All rights reserved.