Designing Trimetallic CoNiFeMOF Synthesized by Electrochemical and Solvothermal Methods and Direct Use Towards Efficient Oxygen Evolution Reaction

Designing a highly efficient and low-cost electrocatalyst for producing hydrogen and oxygen gas as renewable energy through water splitting is essential. Recently, metal–organic frameworks (MOFs) have emerged as decent catalysts with several advantages and better performance than other electrocatalysts. MOFs have been applied for oxygen evolution reaction (OER) to reduce the required energy and increase the kinetic of the reaction. Here, CoNiFeMOFs were successfully synthesized by both solvothermal and electrochemical methods. MIL-101(Fe) was selected as a primary MOF and different cobalt and nickel ratios were optimized for both bimetallic and trimetallic ones. Then, they have been employed as electrocatalysts for OER in 1.0 M KOH solution. Trimetallic MOFs exhibited noticeable electrocatalytic behavior. The over-potentials, at a constant current density of 10 mA cm⁻², and Tafel slopes of S-CoNiFeMOF1 and E-CoNiFeMOF2, were equal to 300 mV, 40.9 mV dec⁻¹ , and 320 mV, 41.2 mV dec⁻¹ , respectively, showing the best electrocatalytic performance towards OER among other synthesized MOFs. Finally, the durability of these electrocatalysts was investigated through a chronoamperometric test in which they exhibited good stability for 12 h.