Electrochemically induced surface modifications of boron-doped diamond electrodes:: an X-ray photoelectron spectroscopy study

The activity of diamond electrodes depends on the chemical state of the diamond surface, and the present work is focussed on understanding how chemical changes either produced in situ electrochemically, or by ex situ plasma treatments, influence the electrochemical properties. Conductive boron-doped diamond electrodes were produced by depositing adherent boron-doped diamond films on tungsten substrates using a hot filament reactor and were characterised by Raman spectroscopy, scanning electron microscopy (SER), high-resolution X-ray photoelectron spectroscopy (XPS) and electrochemical methods. In order to produce electrochemically induced surface modifications, anodic and cathodic polarisation experiments were performed in an aqueous 0.2 M phosphate buffer solution (pH=2). The surface composition of the electrode, as determined by ex situ high-resolution XPS measurements, could be linked to the electrochemical performance of diamond film electrodes. The extent to which changes in surface composition and electrode performance can be controlled and reversed by suitable plasma treatments is explored. (C) 2000 Elsevier Science S.A. All rights reserved.