Structural Reconstruction of a New Cobalt‐Based Metal−Organic Framework for the Efficient Electrocatalytic Hydrogen Production

This study illustrates the fate of a cobalt‐based MOF (CoL1‐MOF) during the hydrogen evolution reaction in 1 M aqueous KOH. The electrocatalytic hydrogen evolution activity of a CoL1‐MOF was evaluated using cyclic voltammetry (CV) in 1 M KOH, with a three‐electrode setup under an N2 atmosphere. The CoL1‐MOF exhibited a 436 mV overpotential to reach a current density of 10 mA/cm2 for hydrogen evolution reaction (HER), while the bare GCE showed negligible activity. Tafel slope of 75 mV/dec revealed CoL1‐MOF follows the Volmer–Heyrovsky mechanism. The intrinsic activity of CoL1‐MOF was further assessed through electrochemical parameters, including electrochemical double‐layer capacitance (Cdl), roughness factor (Rf), and electrochemically active surface area (ECSA), demonstrating enhanced accessibility to active sites. Stability tests showed that CoL1‐MOF maintained consistent HER activity during continuous operation, with a gradual increase in current density due to structural reconstruction. Post‐electrolysis PXRD analysis confirmed the formation of metal hydroxide/oxyhydroxide phases accompanied by morphological changes. Remarkably, the post‐electrolysis CoL1‐MOF demonstrated enhanced HER performance with a reduction in overpotential. This study demonstrates the cost‐effective synthesis of 1D transition metal‐based MOFs and their potential for sustainable hydrogen production, offering a promising solution to the energy crisis.