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. A structurally ordered Ir3V nanoparticle electrocatalyst with the maximized number of neighboring Ir/V bimetallic sites compared to the disordered solid solution counterpart can efficiently promote the water dissociation and thus enhance the electrocatalytic kinetics for hydrogen evolution in alkaline media. [Display omitted] •Structurally ordered intermetallic Ir3V particle catalyst was prepared for catalyzing the HER in alkaline media.•The enhanced HER kinetics is ascribed to the charge redistribution on the ordered Ir3V surface with neighboring Ir/V sites.•The charge redistribution promotes the water dissociation on the electron-deficient V sites.