Accelerated Electrochemical Oxidation of Small Organic Molecules in Hot Aqueous Base Solution

Abstract

To explore fundamentals that could direct more efficient use of small organic molecules in fuel cells, electrooxidation of methanol in aqueous alkaline media has been investigated as a model reaction in an intermediate-temperature range of 80° to 200°C using a pressurized electrochemical cell and by means of voltammetry and chronoamperometry. Well-developed cyclic voltammograms at varying temperature have been obtained using a Ag/AgCl internal reference electrode. It is encouragingly found that the electrooxidation of methanol in alkaline media on high-surface platinum electrode can be substantially accelerated by increasing temperature. The onset potential difference for the electrooxidation of hydrogen and methanol under similar conditions substantially decreases with increasing temperature, characterized by a value of around 50 mV at 150°C. High specific activity of Pt catalysts accessed from chronoamperograms further supports that the methanol electrooxidation is rather facile. These facts are important for the development of high-performance methanol fuel cells.