Core-Shell NiO/C@NiFe-LDH Nanocomposite as an Efficient Electrocatalyst for Oxygen Evolution Reaction

Highly efficient and low-cost oxygen evolution reaction (OER) electrocatalysts have been urgently needed for the development of renewable hydrogen energy via water electrolysis. Herein, a core-shell NiO nanoparticles decorated carbon sphere (NiO/C) and NiFe-layered double hydroxide (NiFe-LDH) nanocomposite (NiO/C@NiFe-LDH) was prepared by a calcination-hydrothermal synthesis approach. In this nanocomposite, NiO/C as the core were derived from Ni based metal organic frameworks (Ni-MOFs), which not only provide a porous and conductive carbon support for NiFe-LDH nanosheets to expose active sites, but also offer a synergistic active site for NiFe-LDH nanosheets. The structure and morphology of NiO/C@NiFe-LDH were mainly characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption test. The OER catalytic activity of NiO/C@NiFe-LDH was optimized by adjusting the ratio between NiO/C and NiFe-LDH and adding bridging agents. Under the optimum conditions, the overpotential at 10 mA cm(-2) for NiO/C@NiFe-LDHs is only 299 mV(vs RHE), lower than that of commercial RuO2 (330 mV). Besides, the NiO/C@NiFe-LDH exhibits a good stability in 10-hour testing. These results show that the ingenious combination of different OER catalysts may be an effective strategy to prepare low-cost OER catalysts with good performance. (C) 2020 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.