Electrochemical behavior of synthetic diamond thin film electrodes

Diamond's chemical inertness and unique electrochemical properties present great potential for a variety of applications in aggressive environments. P reliminary results have shown the widest known electrochemical window befor e water decomposition, allowing new possibilities for both anodic and catho dic reactions. Studies of the oxidation of organic compounds has been perfo rmed with alcohols such as isopropanol, phenol and organic acids. Cyclic vo ltammetry demonstrates no activity in the potential range where water is st able. In the potential region of oxygen evolution, the organic compounds ar e mainly oxidized to CO2. No deactivation or reduction in the thickness of the electrode has been observed. In addition, no fouling of the diamond sur face has been detected. Furthermore, no hydrodynamic effects have been obse rved. Concentrated (1 M) and diluted (3 x 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 effic iency of about 40% for concentrated solutions. At low cyanide concentration s, the current efficiency is strongly increased by the presence of Cl-. Ele ctrochemical reduction of cadmium and copper has been carried out on diamon d electrodes. Non-adherent deposits have been obtained on diamond cathodes. (C) 1999 Elsevier Science S.A. All rights reserved.