Seaweed-Like Structure of a NiCo2O4/NiFe2O4/C Nanoelectrocatalyst: An Effective Strategy for Boosting Overall Water Splitting

Abstract

A material concept constructed of NiCo₂O₄, NiFe₂O₄, and carbon was designed and synthesized by using a two-step process involving hydrothermal and flaming deposition methods and was further applied for overall water splitting. In this study, the electrocatalytic activities of NCO/NFO/C in alkaline conditions were studied and compared to its single phase of NiCo-LDH, NiCo₂O₄, and NiFe₂O₄, including the materials characterization (e.g., scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman analyses). NCO/NFO/C was found as a 3D seaweed-like structure with an average particle size of 43.7 ± 2.1 nm. NCO/NFO/C electrocatalysts possess lower hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) overpotentials of 242 and 240 mV at 100 mA·cm^–2 as well as smaller Tafel slope values of 54 and 31 mV·dec^–1, respectively. Notably, NCO/NFO/C can be utilized as a bifunctional electrocatalyst for overall water splitting. NCO/NFO/C demonstrates a minimum cell voltage of 1.7 V at a current density of 100 mA·cm^–2. This work emphasizes the excellent electrocatalytic performances of NCO/NFO/C for overall water splitting as well as the facile synthesis technique.