Rational Design and Engineering of Metal-Organic Framework-Derived Trimetallic NiCoFe-Layered Double Hydroxides as Efficient Electrocatalysts for Water Oxidation Reaction

The development of active, noble-metal-free electrocatalysts for the oxygen evolution reaction (OER) with low cost and high earth abundance for energy-efficient electrolysis applications has been a challenging task. In this study, a two-step chemical process that involves co-precipitation followed by alkaline treatment is proposed to fabricate trimetallic NiCoFe-layered double hydroxide (t-NiCoFe-LDH) materials for OER using trimesic acid as a metal-organic framework (MOF) ligand. Owing to the unique aloe-vera-leaf-like morphology and high porosity of the prepared t-NiCoFe-LDH, it showed improved electrocatalysis for OER in an alkaline solution by providing hot spots and facilitating electrolyte penetration into the uniform channels, further increasing the contact area between the active material and electrolyte. Higher electrocatalytic activity was observed for t-NiCoFe-LDH in comparison with pristine MOF-derived catalysts and commercial RuO₂and IrO₂catalysts. A current density of 10 mA cm^-2was achieved with an overpotential of 277 mV and a Tafel slope of 68.83 mV dec^-1in 1.0 M KOH. Additionally, no surface leaching was observed after continuous electrolysis for 50 h. The findings of this study suggest a facile and easy approach to designing ternary MOF-derived LDH structures with different combinations and ratios of metals to develop multicomponent electrocatalytic systems.