MOF-Derived NiO/NiCo₂O₄ and NiO/NiCo₂O₄-rGO as Highly Efficient and Stable Electrocatalysts for Oxygen Evolution Reaction

Abstract

We developed a hydrothermal synthesis and high temperature calcination method to synthesize the metal–organic framework (MOF)-derived NiCo2O4/NiO and NiCo2O4/NiO-rGO. These composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Brunner–Emmet–Teller measurements. This work combines excellent catalytic efficiency of the transition metal with large specific surface area and large number of pores of the MOF. Consequently, catalysts for oxygen evolution with high efficiency and low cost were obtained. Both materials show lower overpotential at 430 and 350 mV, respectively, under 10 mA·cm–2. The Tafel slopes are 49 and 66 mV·dec–1, respectively, with very small performance attenuation for long-term catalytic reaction. Therefore, the catalysts reported herein possess great potential for application in oxygen evolution reaction.