Low-Iridium-Content IrNiTa Metallic Glass Films as Intrinsically Active Catalysts for Hydrogen Evolution Reaction.

Abstract

Although various catalytic materials have emerged for hydrogen evolution reaction (HER), it remains crucial to develop intrinsically effective catalysts with minimum uses of expensive and scarce precious metals. Metallic glasses (MGs) or amorphous alloys show up as attractive HER catalysts, but have so far limited to material forms and compositions that result in high precious-metal loadings. Here, an Ir₂₅ Ni₃₃ Ta₄₂ MG nanofilm exhibiting high intrinsic activity and superior stability at an ultralow Ir loading of 8.14 µg cm^-2 for HER in 0.5 m H₂ SO₄ is reported. With an overpotential of 99 mV for a current density of 10 mA cm^-2 , a small Tafel slope of 35 mV dec^-1 , and high turnover frequencies of 1.76 and 19.3 H₂ s^-1 at 50 and 100 mV overpotentials, the glassy film is among the most intrinsically active HER catalysts, outcompetes any reported MG, representative sulfides, and phosphides, and compares favorably with other precious-metal-containing catalysts. The outstanding HER performance of the Ir₂₅ Ni₃₃ Ta₄₂ MG film is attributed to the synergistic effect of the novel alloy system and amorphous structure, which may inspire the development of multicomponent alloys for heterogeneous catalysis.