Self-reconstruction in self-supporting MOF-74 electrode to enhance electrocatalytic oxygen evolution

Understanding the self-reconstruction process of metal-organic frameworks (MOFs) in alkaline electrolytes is extremely important for the development of efficient electrocatalysts for the oxygen evolution reaction (OER). In this study, we synthesized MOF-74 in-situ on activated nickel-iron foam (NFF) to create a self-supporting MOF-74/NFF(40) electrode without the need for an imposed metal species. It was found that the prepared MOF-74/NFF(40) electrode possessed the best electrocatalytic OER performance, which can achieve the current density of 10, 50, 100 mA cm−2 in 1 M KOH at overpotentials of 227,295 and 357 mV, respectively. X-ray photoelectron spectroscopy (XPS) revealed that the OER process altered the local electron structure of Fe and Ni atoms, resulting in electron transfer from Fe to Ni and promoting oxygen production through bimetallic synergy. Furthermore, the electrochemical reconstruction process on the electrode surface in-situ generated metal hydroxides and hydroxyl oxides, which acted as the main active species to accelerate OER. This study presents a simple and effective approach for synthesizing high-performance and long-lasting MOF-based electrocatalysts for OER.