Two-Dimensional NiCo2S4 Nanosheets Deliver Efficient Oxygen Evolution Reaction

Introduction: The development of cost-effective and efficient catalysts plays a pivotal role in the realization of hydrogen production through electrochemical water splitting. Method: In this study, two-dimensional NiCo2S4 nanosheets weresynthesized usinga hydrothermal method followed by a sulfidation process. Results: The resulting materials were thoroughly characterized to understand their morphology and structure. The findings indicate that the NiCo2S4 nanosheets exhibit exceptional electrical conductivity and a high density of pores, which facilitate electrolyte infiltration and interfacial charge transfer during electrochemical reactions. Furthermore, the incorporation of S2− modulates the electronic structure of metal ions, reducing the oxidation potential of metal sites and promoting the surface reconstruction of the electrode to form active species. Electrochemical tests conducted in a 1 M KOH solution using the synthesized catalyst as the working electrode demonstrate an overpotential of merely 280 mV and 300 mV at a current density of 20 mA cm−2 and 40 mA cm−2 , respectively, which are much lower than those of NiCo-LDH electrodes (360 mV and 410 mV). Conclusion: Furthermore, the NiCo2S4 electrode delivers a remarkably low Tafel slope of 47.9 mV dec−1 . This investigation presents a novel approach to the development of efficient transition metal-based electrocatalysts.