Electrocatalytic oxidation of low weight oxygenated organic compounds: A review on their use as a chemical source to produce either electricity in a Direct Oxidation Fuel Cell or clean hydrogen in an electrolysis cell

Abstract

The electrocatalytic oxidation of low weight oxygenated compounds, such as formic acid and methanol, has been the subject of many investigations since nearly fifty years both for their use in a Direct Oxidation Fuel Cell or to produce clean hydrogen by their electrochemical reforming in an Electrolysis Cell. To optimize the energy efficiency of these processes it is very important to know the reaction mechanisms of their electro-oxidation on suitable and specific electrocatalysts. Andrzej Więckowski, together with Roger Parsons, were among the major scientists involved in the determination of the reaction mechanisms of their oxidation on noble metal electrodes both by electrochemical methods (such as linear and cyclic voltammetry) and physicochemical methods, e.g. radiometry, NMR and Infrared Spectroscopy. This review paper first presents the thermodynamics and kinetics of the electrocatalytic oxidation of low weight oxygenated compounds, together with the reaction mechanisms of the electrochemical oxidation of formic acid and methanol. Then their use, as basic feedstock in a Direct Oxidation Fuel Cell for electricity production with a relatively good efficiency (≈ 40%) or in a Proton Exchange Membrane Electrolysis Cell for the production of clean hydrogen able to feed low temperature fuel cells, is discussed.