Enhanced water splitting kinetics using MgFeO3/MXene/VS2 hybrid bifunctional catalysts

Abstract

There is a persistent need to propose efficient and durable electrocatalysts established on non-precious, earth-abundant elements to enhance the efficiency of electrochemical water splitting. In this work, perovskite oxide-MgFeO₃ (MFO) nano-cubes were incorporated onto the surface of MXene-Ti₃C₂ sheets and 2D VS₂ through a hydrothermal reaction to form an MgFeO₃/MXene/VS₂ hybrid with a hierarchical porous architecture. By controlling the synergetic properties of the multiple mechanisms of the hybrid, including the high conductivity of MXene/metallic sulfide, a porous-like architecture featuring rich channels for efficient mass and charge transference, and hybridization with electronic construction regulation, the MFO/MXene/VS₂ hybrid exhibited outstanding performance. In particular, MFO/MXene/VS₂ demonstrated exceptional efficiency for the hydrogen evolution reaction, achieving an overpotential of 35 mV at 10 mA cm⁻² and a Tafel slope of 42 mV dec⁻¹. Similarly, it achieved an overpotential of 214 mV at 10 mA cm⁻² for the oxygen evolution reaction, with a corresponding Tafel slope of 54 mV dec⁻¹ in a 1.0 M KOH solution. When employed in an overall water-splitting electrolyzer with an MFO/MXene/VS₂‖MFO/MXene/VS₂ configuration, it achieved a low voltage of 1.47 V to maintain a current density of 10 mA cm⁻² with commendable stability.