Amorphous High-Entropy Alloy Nanoframes: Oxygen Vacancy-Mediated Electronic Regulation in Ni–Nb–Zr–Ti–Cu for Efficient Hydrogen Evolution

Research on transition metal-based high-entropy alloys (HEAs) as electrocatalysts for the hydrogen evolution reaction (HER) is advancing rapidly. In this study, a nanoporous high-entropy amorphous alloy, np-Ni₃₀Nb₂₀Zr₂₀Ti₂₀Cu₁₀, was synthesized via chemical dealloying. The alloy is predominantly amorphous and demonstrates exceptional HER performance, requiring an overpotential of only 61 mV to achieve a current density of 10 mA cm^-2 and exhibiting a Tafel slope of 71.3 mV dec^-1, thereby outperforming most reported Ni-based electrocatalysts. The high-entropy amorphous phase provides abundant active sites and ensures long-term stability. Furthermore, the increased concentration of oxygen vacancies enhances electronic conductivity and promotes charge transfer, while the synergistic interaction between Ni and Cu optimizes the hydrogen adsorption energy. Notably, the np-Ni₃₀Nb₂₀Zr₂₀Ti₂₀Cu₁₀ alloy shows excellent durability, positioning it as a highly promising candidate for practical HER applications. This work offers fundamental insights for the design of advanced electrocatalysts from multicomponent material systems.