Electrocatalytic Potential of Borophene Derivatives in the Oxygen Evolution Reaction

Since borophene and its derivatives exhibit a wide variety of phases, universal fabrication routes have not yet been fully established. In this study, we present a liquid-phase chemical exfoliation method for borophene using acids and oxidants. Unlike the Hummers method for graphite, this approach enables the exfoliation of boron without inducing oxidation. Oxygen species were incorporated by treating the flakes under a hydrogen atmosphere at different temperatures, with changes monitored by X-ray photoelectron spectroscopy (XPS). The B–O/B–B bonding ratio was tuned, and the formation of B2O3 was detected. Higher-temperature treatments introduced defects and holes, as confirmed by TEM, which, in turn, provided active sites for electrocatalysis. Borophene treated at 600 °C in hydrogen proved highly active and durable in the oxygen evolution reaction (OER), achieving a Tafel slope of 100 mV/dec and an electrochemical active surface area (ECSA) of 46 m2/g. Postmortem studies of the sample by means of XPS identified active intermediates, highlighting the borophene potential as a novel metal-free electrocatalyst. This research shows borophene derivaties fabrication and its compositional and morphological tuning for catalytic applications.