Seed-assisted formation of NiFe anode catalysts for anion exchange membrane water electrolysis at industrial-scale current density

Abstract

Alkaline oxygen evolution reaction is critical for green hydrogen production from water electrolysis but encounters great challenges when operated at industry-required ampere-scale current densities, such as insufficient mass transfer, reduced catalytic activity and limited lifetimes. Here we develop a one-step seed-assisted heterogeneous nucleation method (25 °C, 24 h) for producing a nickel–iron-based electrocatalyst (CAPist-L1, where CAP refers to the centre of artificial photosynthesis) for robust oxygen evolution reaction at ≥1,000 mA cm−2. Based on the insoluble nanoparticles in the heterogeneous nucleation system, a dense interlayer is formed that anchors the catalyst layer tightly on the substrate, ensuring stable long-term durability of 15,200 h (>21 months) in 1 M KOH at 1,000 mA cm−2. When applying CAPist-L1 as the anode catalyst in practical anion exchange membrane water electrolysis, it delivers a high activity of 7,350 mA cm−2 at 2.0 V and good stability at 1,000 mA cm−2 for 1,500 h at 80 °C. Anion exchange membrane water electrolysis is a promising technology for H2 production using precious metal-free catalysts, but certain hurdles persist for its broad deployment such as the operational stability of its anode catalyst. Now a seed-assisted heterogeneous nucleation method is put forward to prepare a NiFe catalyst with high activity and a stability of over 21 months at 1 A cm−2.