Synthesis of nickel germanide (Ge12Ni19) nanoparticles for durable hydrogen evolution reaction in acid solutions

Abstract

Desigining advanced materials as electrochemical catalysts for the hydrogen evolution reaction (HER) has caught great attention owing to the growing demand for clean and renewable energy. Nickel (Ni)-based compounds and alloys are promising non-noble-metal electrocatalysts due to their low cost and high activity. However, in most cases, Ni-based compounds and alloys have low durability in acid electrolyte, which limits their application in the electrolytic processes. In this study, monoclinic Ge₁₂Ni₁₉ nanoparticles were synthesized and exhibited high electrocatalytic activity and stability for the HER in acidic solution. Ge₁₂Ni₁₉ nanoparticles achieve an overpotential of 190 mV at cathodic current density of 10 mA cm⁻² and a Tafel slope of 88.5 mV per decade in 0.50 M H₂SO₄ electrolyte. Moreover, the performance is maintained after a 10 000-cycle CV sweep (−0.3 to +0.1 V vs. RHE) or under a static overpotential of −0.7 V vs. RHE for 24 hours. The reported electrocatalytic performance of the Ge₁₂Ni₁₉ nanoparticles sufficiently proves the excellent endurance at lower required active overpotentials in acidic solution, enabling the broad applications of the Ni-based electrocatalysts. Finally, a large-area (5 cm²) electrocatalyst for HER was demonstrated for the first time. The great efficiency of the energy conversion performance sufficiently represented the potential of Ge₁₂Ni₁₉ nanoparticles as electrocatalysts in commercial fuel cells.