Nitrogen-Mediated Lanthanide Electronic Perturbations Boost Oxygen Spillover on Nickel-Iron Electrocatalysts for...

Highly active oxygen evolution reaction catalysts allow high-efficiency water electrolysis for green hydrogen production, but prevalently encounter severe activity degradation when operated at industrial ampere-level current densities. Here we demonstrate configurating heterostructure interfaces in nickel-iron-based catalysts to exceptionally improve their oxygen evolution reaction electrocatalytic durability at >1000 mA cm^-2 by incorporating nitrogen-doped lanthanide oxides, which enable supplementary oxygen intermediate spillover via a modified lattice oxygen mechanism. By virtue of nitrogen-mediated flexible electronic perturbation of cerium, there reversibly form oxygen vacancies in nitrogen-doped cerium dioxide to sustainably accommodate the oxygen intermediates spilled from nickel-iron (oxy)hydroxide and boost *O-O coupling and desorption kinetics, which significantly suppresses the formation of soluble high-valence iron species. This enlists nickel-iron-based heterostructure electrocatalysts with a hierarchical nanoporous architecture to exhibit outstanding oxygen evolution reaction activity and durability, achieving 2000 mA cm^-2 at an ultralow overpotential of 310 mV and maintaining stability for >9000 h in 1 M KOH.