Electrodes of Synthetic Diamond Compacts Added with Platinum: The Platinum Effect on Electrochemical Activity

Abstract

Conducting diamond composite electrodes are prepared by converting graphite into diamond at high pressure and high temperature in two- and three-component growth systems Pt–C and Pt–C–B; physical and electrochemical properties of the compacts are studied. A diamond–platinum-compact electrode grown from the Pt–C two-component system behaves qualitatively as purely platinum one in the chloride ion anodic oxidation reaction, when corrected to the platinum actual quantity at its surface. Voltammetric data well agree with results of electrochemical impedance measurements in f-sweep and E-sweep modes. Diamond doping with boron during the synthesis in the Pt–C–B system provides electrodes electroactive with respect to the chloride ion oxidation reaction; their activity increased with the increasing of platinum content at the electrode surface. The catalyst (platinum) introducing directly onto the diamond-compact surface is shown being still more effective (with respect to the chlorine anodic evolution reaction) than the bulk doping with platinum during the compact synthesis.