Effect of the boron content on the steam activation of boron-doped diamond electrodes

In order to investigate the initial stages of the steam-activation process of boron-doped diamond (BDD) electrodes, polycrystalline BDD electrodes with different levels of boron doping (800, 2500 and 5000ppm) and crystal orientation were treated with water vapor at 800°C. A higher degree of etching was observed for BDD electrodes with higher boron content. Based on scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, it is suggested that the {111} planes are preferentially etched. Thus, high-boron containing BDD electrodes which have a higher abundance of the {111} planes are heavily etched, while low-boron containing BDD electrodes with a mixed surface of {100} and {111} planes are less corroded. The steam activation of BDD electrodes have a higher electrochemically active surface area and wider potential window compared to pristine BDD electrodes.