In Situ Growth of CoFe Bimetallic MOFs on S-Mxene/NF Composite Substrate as an Efficient Electrocatalyst for OER

Fabricating an inexpensive and efficient electrocatalyst for the electrocatalytic oxygen evolution reaction (OER) in an alkaline medium is crucial for renewable energy generation. In this work, nickel foam (NF) modified with few-layer or single-layer MXene (S-MXene) was used as a substrate to prepare an independent, self-supporting composite electrode for oxygen evolution reaction (OER) catalysis. CoFe bimetallic MOF nanosheets were grown in situ on composite substrates by electrodeposition. Compared to multilayer MXene, S-MXene has a larger specific surface area and interlayer spacing, making it an ideal material for enhancing the conductivity of the electrode or serving as a supporting matrix. As an intermediate material, S-MXene can not only reduce the charge transfer resistance of the electrode and improve the active sites but also enhance the structural stability of the electrode, significantly improving the catalytic activity and long-term electrolysis stability of the electrode. The improved CoFe NSs@S-MXene/NF composite electrode delivers a current density of 10 mA cm–2 at a low overpotential value of only 191 mV in 1.0 M KOH, along with an ultralow Tafel slope of 31 mV dec–1. Additionally, the composite electrode exhibits outstanding stability for 24 h during OER at various current densities. This work innovatively uses S-MXene as a base material and develops a highly efficient new type of OER electrode. This novel strategy can serve as a reference for the modification of other electrode materials and expand the application of MXene in the field of water splitting.