A REFERENCE ELECTRODE FOR USE IN METHANOL SOLUTIONS

The choice of a suitable reference electrode for electrochemical testi ng of metals in organic solutions poses a major difficulty. The goal o f this research was to develop a stable, reproducible and minimally co ntaminating reference electrode to be used while conducting electroche mical experiments in methanol solutions of varied compositions. The ap plicability of the Ag/AgCl(Methanol) electrode was investigated. Exami nation of the thermodynamic behavior of this electrode showed that the observed Nernst slope with respect to chloride concentration agreed w ell with theory. The equilibrium potential was also found to vary with water concentration, possibly due to changes in the energy needed to transfer a chloride ion from water to methanol and/or changes in the a ctivity coefficient of chloride, The electrode interface was found to be moderately reversible, with an exchange current density of 3 x 10(- 5) A/cm(2). Further, this electrode was observed to be stable and dura ble for over two years. The water leakage rate from the reference elec trode was found to be quite low over the time periods of relevance for the electrochemical experiments. Copyright (C) 1996 Elsevier Science Ltd.