<p>The electrochemical properties of the hydrogen evolution reaction and the hydrogen storage behavior of Hg-Fe–Ni on graphite (C/Hg-Fe–Ni) were examined in 0.1M NaOH using Cyclic Voltammetry (CV), chronopotentiometry (CP), Tafel polarization, and electrochemical impedance spectroscopy (EIS). The physical features and chemical composition of the alloy were examined using a field emission scanning electron microscope, X-ray diffraction (XRD), and Energy-dispersive X-ray spectroscopy. The electrochemical discharge capacity of C/Hg-Fe–Ni was 20,302 mAh/g, about 6 times higher than that of C/Hg-Ni (3577 mAh/g). The discharge capacity of C/Hg-Ni-Fe in repeated cycles was studied. The electrode’s performance peaks at the 11th cycle, reaching 1 (100% yield), indicating excellent performance. After 140 cycles, the hydrogen evolution reaction activity shows negligible change. In the following, the effects of the applied current, charging duration, and the time lag between charging and discharging on the electrode’s discharge capacity were examined. The C/Hg-Fe–Ni also exhibits significantly superior catalytic efficacy for hydrogen evolution reaction, evidenced by the obtained Tafel slope value, the exchange current density, and over potential that were found to be -91.43 mVdec⁻¹, 1.45 mAcm⁻², and 140 mV (vs. RHE), respectively. The hydrogen diffusion coefficient into the ternary C/Hg-Fe–Ni was also obtained as 1.7 × 10⁻¹⁴ cm² s⁻¹. The C/Hg-Fe–Ni electrode can be recognized as an efficient, easily prepared electrode for both electrochemically hydrogen storage and hydrogen evolution reaction.</p> Graphical abstract <p></p>