Templated Synthesis of Defect-Rich Metal–Organic Frameworks for Efficient Oxygen Evolution Electrocatalysis

Abstract

Metal–organic frameworks (MOFs) have been widely explored in oxygen evolution reaction (OER) electrocatalysis due to their tunable structures, high surface area, and abundant active sites. During OER process, MOFs transform into metal oxyhydroxides, which serve as actual active species for oxygen evolution. Therefore, the rational design of MOFs to enhance this transformation is crucial for achieving superior OER performance. In this study, nickel-cobalt layered double hydroxide (NiCo-LDH) is used as a 2D template for MOF synthesis, and both 2,6-naphthalenedicarboxylic acid (NDC) and defect ligand ferrocenecarboxylic acid (Fc) are introduced to convert the hydroxide precursor to a defect-rich MOF material (NiCo-NDC-Fc/NF), which directly applies as an OER electrocatalyst. This strategy enables the construction of coordination defects in MOFs, exposing a large number of unsaturated metal sites that facilitated catalyst reconstruction, leading to outstanding OER activity. The NiCo-NDC-Fc/NF catalyst exhibits remarkably low overpotentials of only 219 and 254 mV at current densities of 10 and 100 mA cm⁻², respectively. Furthermore, this catalyst also demonstrates excellent stability after operating at 60 mA cm⁻² for 100 h. This work offers a facile method for the effective construction of defective MOFs, and provides valuable reference for the design of MOF-based electrocatalysts.