A Bimetallic-Doped Boron Nanosheet Electrocatalyst for Efficient Hydrogen Evolution Reaction

Two-dimensional (2D) monometal boron nanosheets (BNS) are emerging as a promising candidate, demonstrating high catalytic performance by virtue of their tunable surface chemistry, large surface area, superb hydrophilicity, and swift charge transfer kinetics. Nonetheless, oxidation and restacking of these nanosheets in ambient air make it challenging for practical applications. The introduction of transition metals in BNSs helps to suppress interlayer restacking of the sheets. Further, the addition of bimetallic atoms help to diminish the overpotential value, correspondingly boosting the catalytic activity and onset potential required for reaction kinetics. Accordingly, herein, structural and electronic engineering of BNS using bimetallic atoms (Ag:Cu) at different doping concentrations are investigated and characterized using x-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and x-ray photoelectron spectroscopy studies. Finally, the electrocatalytic performance towards hydrogen evolution reaction was investigated through cyclic voltammetry and electrochemical impedance spectroscopy to study the charge transfer rate. Here, optimized sample shows lowest overpotential value of 101 mV and Tafel slope of 59 mV dec⁻¹ with highest exchange current density of 7.86 mA cm⁻² and minimum charge transfer resistance of 15.9 Ω. Thus, current findings could help in developing the ideas for the surface modifications to significantly enhance the electrocatalytic performance.