Porous Ni3Si intermetallics as electrocatalysts for hydrogen evolution reaction

Abstract

Designing a stable, low-cost, and efficient electrocatalyst is the key to promoting electrolytic hydrogen production. Herein, a porous Ni3Si electrode with excellent HER activity prepared by elemental powder reaction synthesis and chemical etching is reported. The microstructure analysis results show that the porous Ni–Si material prepared with an atomic ratio of 3:1 is composed of a single Ni3Si phase. After etching treatment, the pore structure of the porous Ni3Si electrode increased significantly, and its specific surface area increased by nearly 40 times. According to the findings of the hydrogen evolution tests, the etched Ni3Si electrode performs better than the Ni3Si electrode in terms of hydrogen evolution, and at a current density of 10 mA cm−2, its overpotential is −116 mV. Meanwhile, the Ni3Si electrode exhibits good HER stability over 24 h and maintains this HER activation beyond 1000 cycles. The hydrogen free-energy of adsorption is calculated by means of density functional theory. It was shown from the analysis that the optimal active site for H∗ adsorption is on the Ni atom and that ΔGH∗ is 0.086 eV, demonstrating the business feasibility of aqueous electrolytic hydrogen creation at a porous Ni3Si electrode.