Structurally ordered intermetallic Ir3V electrocatalysts for alkaline hydrogen evolution reaction

Electrocatalysis of hydrogen evolution reaction (HER) in alkaline media is critical for the practical implementation of economical water-alkali electrolyzers. However, the sluggish water dissociation kinetics even on platinum-based electrocatalysts result in poor hydrogen-production activities. Here we report a structurally ordered Ir3V catalyst for efficiently catalyzing HER in alkaline media. The ordered Ir3V catalyst exhibits a low overpotential of 9.0 mV at 10 mA cm−2 in 1.0 M KOH electrolyte with Ir loading of 19 µg cm−2, corresponding a mass activity of 1200 A gIr−1 at the overpotential of 20 mV, which is 6.7, 9.4, and 3.3 times greater than that of the commercial Pt/C, Ir/C, and disordered Ir3V catalysts. The enhanced HER kinetics is ascribed to the charge redistribution on the ordered Ir3V surface with the maximized number of neighboring bimetallic Ir/V sites compared to the disordered solid solution counterpart, which promotes the water dissociation on the electron-deficient V sites.