Ultrafast wear of boron-doped diamond electrodes induced by pulsed bipolar activation

Abstract

Boron-doped diamond (BDD) electrodes are renowned for their exceptional stability. However, we reveal here for the first time an unexpectedly rapid wear of BDD occurring while applying bipolar pulsed activation, even under moderate conditions (0.1 M Na₂SO₄, current densities ≤ ±50 mA·cm⁻²). Wear was systematically evaluated using gravimetric analysis, scanning electron microscopy (SEM), Raman mapping, and X-ray photoelectron spectroscopy (XPS). At current density of ±50 mA·cm⁻², pulsed activation produced pronounced intergranular erosion and progressive grain detachment, leading to substantial thickness loss (~123 nm·h⁻¹). By contrast, lower-current activation (±5 mA·cm⁻²) resulted in attenuated, self-limiting corrosion at a reduced rate (~12.6 nm·h⁻¹). Raman mapping revealed graphitization, while XPS evidenced rapid surface oxidation (C–O, O–C=O) with preserved sp³ bonding of the near-surface, suggesting that any surface sp² carbon is transient and rapidly etched. Despite thousands of activation cycles and significant material removal, the near-surface chemistry remained structurally diamond-like, ensuring reproducible electroanalytical performance. These findings provide practical guidelines for optimizing pulsed activation protocols, enabling efficient electrode cleaning with preserved sensitivity, reproducibility, and extended lifetime in electrochemical applications.

Keywords: Boron-Doped Diamond (BDD), Electrode wear, Pulsed bipolar activation, Electrochemical stability