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

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.