Electrocatalytic water splitting by bifunctional Zircon-doped borophene

Abstract

Oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are crucial for renewable energy technologies such as water splitting. Borophene, a two-dimensional (2D) boron material, has attracted significant interest for its unique electron deficiency and potential applications in energy conversion. However, practical studies on borophene’s electrocatalytic performance remain limited. Here, we demonstrate a strategy to enhance the bifunctional electrocatalytic activity in HER and OER of borophene by doping with zirconium compounds. The addition of Zr to boron enhances electrocatalytic properties by improving performance in both OER and HER, achieving overpotentials and Tafel slopes of 252 and 240 mV, 43 and 203 mV/dec, respectively. Additionally, conducting the measurements at 40 °C led to achieving the overall water-splitting potential of 1.541 (V vs. RHE). Stability tests over 1000 h at ± 10 mA/cm2 highlight the composite’s robustness, outperforming Pt/C in HER and matching the stability of RuO₂ in OER. Ex-situ analyses: X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and X-ray diffraction (XRD) reveal insights into the chemical structure evolution during the electrochemical process. This study not only advances the understanding of borophene’s electrocatalytic mechanisms but also paves the way for its application in efficient and sustainable energy technologies.