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

Abstract

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.