Unlocking Peak Efficiency in Anion-Exchange Membrane Electrolysis with Iridium-Infused Ni/Ni2P Heterojunction Electrocatalysts

Abstract

Developing cost-effective, highly efficient, and durable bifunctional electrocatalysts for water electrolysis remains a significant challenge. Nickel-based materials have shown promise as catalysts, but their efficiency in alkaline electrolytes is still lacking. Fascinatingly, Mott–Schottky catalysts can fine-tune electron density at interfaces, boosting intermediate adsorption and facilitating desorption to reduce the energy barrier. In this study, iridium-implanted Mott–Schottky Ni/Ni₂P nanosheets (Ir_SA–Ni/Ni₂P) is introduced, which are delivered from the metal–organic framework and employ them as the bifunctional catalysts for water electrolysis devices. This catalyst requires a small 54 mV overpotential for hydrogen evolution reaction (HER) and 192 mV for oxygen evolution reaction (OER) to reach 10 mA·cm⁻² in a 1.0 m KOH electrolyte. Density functional theory (DFT) calculations reveal that the incorporation of Ir atoms with enriched interfaces between Ni and Ni₂P can promote the active sites and be favorable for the HER and OER. This discovery highlights the most likely reactive sites and offers a valuable blueprint for designing highly efficient and stable catalysts tailored for industrial-scale electrolysis. The Ir_SA-Ni/Ni₂P electrode exhibits exceptional current density and outstanding stability in a single-cell anion-exchange membrane electrolyzer.