Electrochemical selectivity for redox systems at oxygen-terminated diamondelectrodes

Oxygen-terminated diamond electrodes were prepared by exposing as-grown hyd rogen-terminated diamond thin films to oxygen plasma. The as-grown surfaces , which were highly hydrophobic, become hydrophilic after the oxygen plasma treatment. The apparent surface conductivity was not significantly changed after the oxygen plasma treatment. However, the electrochemical responses to several redox systems became remarkably different. For example, the cycl ic voltammetric anodic-cathodic peak separations for the oxygen-terminated diamond electrodes became extremely large compared to those for the as-grow n electrodes. This behavior was examined in comparison with as-grown diamon d and glassy carbon electrodes. (C) 1999 Elsevier Science S.A. All rights r eserved.