Abstract
In present study, we report hydrothermal synthesis of reduced graphene oxide (RGO) supported NiMoO4-nanorods (NRs) nanocomposites (NiMoO4-NRs@RGO nanocomposites) for electro-catalysis of water to oxygen evolution and reduction reactions (OER/ORR). The prepared nanocomposites were characterized by x-ray diffraction (XRD), Raman, Fourier transform infrared (FTIR), high resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), energy dispersive and x-ray photoelectron spectroscopy (XPS) techniques. The electrochemical performances of NiMoO4-NRs@RGO nanocomposites were examined in 0.5 M KOH (alkaline electrolyte) using cyclic voltammetry (CV), linear sweep voltammetry (LSV), Tafel and chronoamperometry (CA) electrochemical techniques at room temperature. The onset over-potentials of NiMoO4-NRs@RGO nanocomposite for ORR and OER were found to be of similar to 75 and similar to 185 mV, respectively, while the Tafel slopes for OER and ORR were observed to be similar to 54 and similar to 245 mV/dec respectively. The involved electrons (i.e. 4e(-)) in redox reactions were calculated using rotating disc electrode experiments. Based on admirable electro-catalytic performance of NiMoO4-NRs@RGO nanocomposites with low energy loss, suggesting it as cost effective and efficient OER/ORR electro-catalysts compared to noble metal electro-catalysts. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.