Interface-Engineered NiFe/Ni-S Nanoparticles for Reliable Alkaline Oxygen Production at Industrial Current: A Sulfur Source Confinement Strategy

Abstract

Using powder-based ink appears to be the most suitable candidate for commercializing the membrane electrode assembly (MEA), while research on the powder-based NPM catalyst for anion exchange membrane water electrolyzer (AEMWE) is currently insufficient, especially at high current density. Herein, a sulfur source (NiFe Layered double hydroxide adsorbed ${\mathrm{SO}}_4^{2-}$ ) confinement strategy is developed to integrate Ni₃ S₂ onto the surface of amorphous/crystalline NiFe alloy nanoparticles (denoted NiFe/Ni-S), achieving advanced control over the sulfidation process for the formation of metal sulfides. The constructed interface under the sulfur source confinement strategy generates abundant active sites that increase electron transport at the electrode-electrolyte interface and improve ability over an extended period at a high current density. Consequently, the constructed NiFe/Ni-S delivers an ultra-low overpotential of 239 mV at 10 mA cm^-2 and 0.66 mA ${\mathrm{cm}}_{\mathrm{ECSA}}^{-2}$ under an overpotential of 300 mV. The AEMWE with NiFe/Ni-S anode exhibits a cell voltage of 1.664 V @ 0.5 A cm^-2 and a 400 h stability at 1.0 A cm^-2 .

Keywords: anion exchange membrane water electrolyzer; confinement strategy; nanoparticle; oxygen evolution reaction.