Rational engineering of a tetrametal-organic framework for enhanced electrocatalytic oxygen evolution

Exploring robust and cost-effective multicomponent electrocatalysts is crucial for enhancing the diversity of active sites in water oxidation processes. Metal-organic frameworks (MOFs) have garnered significant attention as promising electrocatalysts due to their tunable chemical compositions and structural flexibility. Herein, tetrametallic NiFeCoV-MOF-74 nanospheres, with distinctive triangular protrusions, were prepared by a facile one-step solvothermal method. The as-synthesized catalysts demonstrate superior oxygen evolution reaction (OER) performance under alkaline conditions. Specifically, the NiFeCoV-MOF-74 displays a low overpotential of 266 mV at a current density of 10 mA cm^-2 and a Tafel slope of 32.7 mV dec^-1, outperforming commercial RuO₂ and other catalytic reference samples. Additionally, the catalyst exhibits outstanding long-term stability, maintaining its activity for 100 h even at 100 mA cm^-2. Comprehensive characterization through X-ray photoelectron spectroscopy and in situ Raman spectroscopy reveals that the electrochemically generated NiOOH and CoOOH serve as the real active sites, significantly enhancing OER activity. Furthermore, a multimetallic synergistic effect, facilitated by electron transfer among Ni, Fe, Co, and V elements, substantially accelerates the OER kinetics. This work highlights the importance of designing multimetallic MOFs with optimized compositions for advanced electrochemical energy conversion systems.