A review on NiFe-based electrocatalysts for efficient alkaline oxygen evolution reaction

Oxygen evolution reaction (OER) is an essential electrochemical reaction in water-splitting and rechargeable-metal-air-batteries to achieve clean energy production and efficient energy-storage. At first, this review discusses about the mechanism for OER, where an oxygen molecule is produced with the involvement of four electrons and OER intermediates but the reaction pathway is influenced by the pH. Then, this review summarizes the brief discussion on theoretical calculations, and those suggest the suitability of NiFe based catalysts for achieving optimal adsorption for OER intermediates by tuning the electronic structure to enhance the OER activity. Later, we review the recent advancement in terms of synthetic methodologies, chemical properties, density functional theory (DFT) calculations, and catalytic performances of several nanostructured NiFe-based OER electrocatalysts, and those include layered double hydroxide (LDH), cation/anion/formamide intercalated LDH, teranary LDH/LTH (LTH: Layered-triple-hydroxide), LDH with defects/vacancies, LDH integrated with carbon, hetero atom doped/core-shell structured/heterostructured LDH, oxide/(oxy)hydroxide, alloy/mineral/boride, phosphide/phosphate, chalcogenide (sulfide and selenide), nitride, graphene/graphite/carbon-nano-tube containing NiFe based electrocatalysts, NiFe based carbonaceous materials, and NiFe-metal-organic-framework (MOF) based electrocatalysts. Finally, this review summarizes the various promising strategies to enhance the OER performance of electrocatalysts, and those include the electrocatalysts to achieve ~1000 mA cm⁻² at relatively low overpotential with significantly high stability.