Stability of H‐terminated BDD electrodes: an insight into the influence of the surface preparation

EIS, CV and XPS experiments were carried out to address the evolution of H-terminated BDD electrochemical properties under intensive use and air aging. A drastic drop of apparent electron transfer rate k' 0 was thus recorded using Fe(CN 6 ) 3-/4- as the redox mediator by identifying components of the Randles equivalent circuit. Excellent agreement was observed between theoretical and experimental curves. The feasibility of recovering and stabilizing high reactivity and reversible behaviour by applying a suitable electrochemical post treatment was then demonstrated. Such a treatment was developed empirically and seemed to significantly improve the electrode performances. On the basis of our results, we claim that the electrochemical evolutions observed are strongly linked to chemical termination modifications and partial inactivation of the electrode surface. Further research on the mechanisms that govern electron mediation at the diamond surface would be of high interest for better control of diamond electrode stability and reactivity towards their applications for bio-electronic devices.