Electrochemical preconditioning of moderately boron doped diamond electrodes: Effect of annealing

This paper is concerned with the study of electrochemical preconditioning on moderately boron doped diamond electrodes. Samples were submitted to an isothermal annealing at 1100 °C in order to outgas the hydrogen introduced into the layer during the deposition process. Consequences of anodic and cathodic galvanostatic steps (1 C cm− 2), in H2SO4 0.5 M, have been studied on both as-deposited samples and annealed ones, by capacitance measurements, cyclic voltammetry in presence of Ce4+/3+ redox system and XPS measurements. The results of Mott–Schottky plots and current voltage curves show that the electrochemical responses of BDD electrodes are strongly influence by annealing. After preconditioning, an enhancement of charge transfer is observed for as-deposited samples, while a more and more passivated behavior is recorded for annealed electrodes. On as-deposited samples a “new” superficial conductive layer linked to the creation of surface defects high above the valence band, is suggested after a specific electrochemical treatment which is not possible on annealed ones.