Electrochemical behavior of synthetic diamond thin film electrodes

Abstract

Diamond's chemical inertness and unique electrochemical properties present great potential for a variety of applications in aggressive environments. Preliminary results have shown the widest known electrochemical window before water decomposition, allowing new possibilities for both anodic and cathodic reactions. Studies of the oxidation of organic compounds has been performed with alcohols such as isopropanol, phenol and organic acids. Cyclic voltammetry demonstrates no activity in the potential range where water is stable. In the potential region of oxygen evolution, the organic compounds are mainly oxidized to CO 2 . No deactivation or reduction in the thickness of the electrode has been observed. In addition, no fouling of the diamond surface has been detected. Furthermore, no hydrodynamic effects have been observed. Concentrated (1 M) and diluted (3×10 −4 M) cyanide solutions have been oxidized on diamond electrodes both in the presence and in the absence of chloride ions. The results show a direct oxidation with a current efficiency of about 40% for concentrated solutions. At low cyanide concentrations, the current efficiency is strongly increased by the presence of Cl − . Electrochemical reduction of cadmium and copper has been carried out on diamond electrodes. Non-adherent deposits have been obtained on diamond cathodes.