Cobalt(II)‐MOF‐Derived Electrocatalysts for Durable Water Oxidation: Ambient Synthesis Versus Solvothermal Synthesis

ABSTRACT The development of low‐cost and efficient electrocatalysts for water oxidation remains a significant challenge in the field of energy conversion. Herein, we report the synthesis of a metal organic framework, CoMOF‐74, under two different conditions, yielding materials with different morphologies: nanoscale particles ( CoMOF‐74/RT ) via room temperature wet‐synthesis and conventional spindle‐shaped bulk crystals ( CoMOF‐74/ST ) through solvothermal synthesis. We have also compared the electrochemical activity of CoMOF‐74 with other well‐known Co‐based MOFs like Co‐BDC, Co‐BTC, and ZIF‐67. Electrochemical evaluation reveals that CoMOF‐74/RT exhibits superior oxygen evolution reaction (OER) activity, delivering a current density of 100 mA cm −2 at an overpotential of 396 mV, along with a Tafel slope of 58 mV dec −1 , outperforming its crystalline counterpart. Notably, CoMOF‐74/RT demonstrates excellent operational stability over a period of 7 days at 100 mAcm −2 . Post‐electrolysis characterization reveals the transformation of the CoMOF‐74/RT into Co(OH) 2 nanosheets, which indicates that the MOF is a pre‐catalyst for the oxygen evolution reaction in the alkaline medium. This study underscores the advantages of room temperature synthesis over high temperature hydrothermal method, emphasizing the influence of morphology on the electrocatalytic performance of MOF‐based materials and providing insights into designing durable OER catalysts.