Facile preparation of Ni-Hg-Fe amalgam for hydrogen evolution reaction in NaOH solution

Abstract

An alloy of Ni-Hg-Fe was synthesized on a graphite electrode using direct current electrodeposition to facilitate the hydrogen evolution reaction under alkaline circumstances. The alloy’s performance showcased outstanding catalytic properties, as demonstrated by the value of overpotential (324 mV at 10 mAcm⁻²), an exchange current density of 1.11 × 10^–1 mAcm⁻², and an activation energy of 4.419 J/mol. A comparison between Ni-Hg-Fe and Ni-Hg alloys revealed that the inclusion of iron notably improved catalytic efficacy, as evidenced by the turnover frequency (Ni-Hg-Fe: 0.8487 H₂ s⁻¹, Ni-Hg: 0.2408 H₂ s⁻¹), decreased charge transfer resistance (Ni-Hg-Fe: 49.96Ω, Ni-Hg: ~ 115Ω), and higher double-layer capacitance (Ni-Hg-Fe: 1.4 mF cm²⁻, Ni-Hg: 0.50 mFcm⁻²). The alloy’s effectiveness is ascribed to the synergistic effect of nickel and iron, as well as the enhanced surface area resulting from iron doping. X-ray diffraction was used to analyze the surface, along with the use of Energy-dispersive X-ray spectroscopy and scanning electron microscopy for surface characterization.