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 dia mond surface, and the present work is focussed on understanding how chemica l changes either produced in situ electrochemically, or by ex situ plasma t reatments, influence the electrochemical properties. Conductive boron-doped diamond electrodes were produced by depositing adherent boron-doped diamon d films on tungsten substrates using a hot filament reactor and were charac terised by Raman spectroscopy, scanning electron microscopy (SER), high-res olution X-ray photoelectron spectroscopy (XPS) and electrochemical methods. In order to produce electrochemically induced surface modifications, anodi c 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 co ntrolled and reversed by suitable plasma treatments is explored. (C) 2000 E lsevier Science S.A. All rights reserved.