NiMOF-FeOOH/NF composites for highly efficient oxygen evolution reaction

Abstract

Metal-organic frameworks (MOFs) have emerged as promising catalysts for the oxygen evolution reaction (OER) in water electrolysis. This study synthesizes a nickel-based MOF on a nickel foam substrate (NiMOF/NF) via a solvothermal method and fabricates NiMOF-FeOOH/NF composites through Fe electrodeposition. The NiMOF-FeOOH₆₀₀/NF composite, prepared with a 600 s electrodeposition time, exhibits an overpotential of 320 mV at 20 mA·cm^-2 and a Tafel slope of 126 mV·dec^-1. Compared to unmodified NiMOF/NF, the overpotential was reduced by 320 mV and the Tafel slope by 146 mV dec^-1. In addition, no significant performance degradation was observed during the 40 h stability test. Further results demonstrated that deposition of Fe ions significantly improved the intrinsic conductivity of NiMOF/NF, enabling more efficient charge transfer during the OER process. Additionally, the modified FeOOH surface morphology increased the number of accessible active sites and enhanced the exposure of catalytic centers. In summary, these structural and electronic modifications synergistically improve the overall catalytic performance and have guiding significance for the application of MOF to OER.