NiFe-LDH electrocatalysts for alkaline water oxidation: Structures, mechanistic pathways, and enhancement strategies

Hydrogen production via water electrolysis hinges on efficient, earth-abundant electrocatalysts that can sustain performance under industrial conditions. NiFe-layered double hydroxides (NiFe-LDHs) have emerged as one of the most active, low-cost catalysts for the oxygen evolution reaction (OER) in alkaline media, owing to their tunable layered structure, favorable Ni-Fe synergism, and compatibility with diverse modification strategies. This review summarizes recent advances in NiFe-LDHs, emphasizing structural and chemical properties that govern catalytic activity, scalable synthesis routes including co-precipitation, epoxide-driven routes, and hydrothermal methods and how these routes shape defect chemistry and phase evolution, mechanistic insights spanning adsorbate evolution, lattice oxygen participation, and emerging oxide pathways, and strategies to boost performance and stability through doping, conductive hybridization, and defect engineering. We highlight notable performance milestones at industrially relevant current densities, analyze trade-offs between activity and durability, and discuss trends in operando/in-situ characterization that reveal active phases and evolving active sites under operation. Finally, the review outlines remaining challenges, scaling, material stability under seawater exposure, and integration into full electrolyzer stacks and identifies prioritized research directions toward robust and bifunctional NiFe-LDH based catalysts for green hydrogen technologies.