Modulating the electronic structure of Ru using a self-reconstructed MOF-NiFeOOH heterointerface for improved electrocatalytic water splitting

Abstract

Constructing efficient and stable electrocatalysts via electrochemical self-reconstruction is an effective strategy to achieve hydrogen evolution. Herein, as predicted by DFT, the construction of the MOF-NiFeOOH heterointerface can effectively regulate the electronic environment of Ru and the adsorption energy of hydrogen and water. Accordingly, a sandwich-like RuNiFe-MOF/NFF electrode was fabricated on a nickel–iron foam (NFF) using subsequent immersion and solvothermal methods. Through electrochemical self-reconstruction, the NiFe site underwent oxidation to a hypervalent state, forming a MOF-NiFeOOH heterojunction. The resulting Ru₁₀NiFeOOH-MOF/NFF exhibited an overpotential of 15 mV@10 mA cm⁻² for the hydrogen evolution reaction (HER) and could be stabilized for 100 h. Moreover, when combined with NiFeOOH-MOF/NFF as the anode, the constructed cell demonstrated a low voltage of 1.51 V@10 mA cm⁻² and long-term durability. The outstanding efficiency of Ru₁₀NiFeOOH-MOF/NFF can be credited to its intrinsic activity, the in situ reconstruction of the MOF, and the rearrangement of charges surrounding the active sites. This work makes a lot of sense for the design and understanding of the self-reconstruction and performance improvement mechanism of MOF-based electrodes.