Synergetic effect of Ni substitution and induced porosity: Enhancing the electrocatalytic performance of cobaltite towards OER and MOR in alkaline medium

The quest for sustainable and efficient energy conversion technologies has intensified research into advanced materials for electrochemical reactions, such as the oxygen evolution reaction (OER) and methanol oxidation reaction (MOR). Transition metal oxides have emerged as promising catalysts due to their abundance, low cost, and adjustable electronic properties. Among these, Nickel (Ni)-based compounds are particularly noteworthy for their catalytic activity and stability. This research paper explores the crucial impact of Nickel (Ni) substitution and introducing porosity on the valence states of metal ions and their mass transport in the context of OER and MOR. In this study, we present a step-by-step surfactant (Brij 58) assisted synthesis approach for the preparation of mesoporous CoO and NiCoO. The synthesised material has been physiochemically characterised by Fourier transform Infrared Spectroscopy (FTIR), Scanning electron microscopic/Energy-dispersive X-ray spectroscopy (SEM/EDS) and High-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and inductively coupled plasma mass spectrometry (ICP-MS) analyses. Additionally, the impact of these alterations on electrocatalytic activity, reaction kinetics, and electrochemical stability during OER/MOR has been explored by Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), Tafel, Electrochemical Impedance Spectroscopy (EIS) and chronoamperometric experiments. Mesoporous NiCoO exhibits exceptional electrocatalytic performance with current densities of 46.8 mA/cm for OER and 214.5 mA/cm for MOR at 550 mV. By shedding light on the intricate interplay between metal substitution, porosity, and valence states, this research aims to provide valuable insights for the evolution of enhanced cobaltite electrocatalysts for sustainable water splitting and MOR.