Co3O4 derived ZnO: An effective electrocatalyst for oxygen evolution reaction in alkaline media

Abstract

The growing accessibility of hydrogen and renewable energy sources has led to a rising significance of cobalt oxide (Co3O4)-based electrocatalysts in the context of effective electrochemical water splitting. Among two-half cell reactions, oxygen evolution reaction (OER) is more complicated and sluggish in behaviour. We present a composite material based on cobalt oxide-derived zinc oxide (Co3O4@ZnO) prepared through a wet chemical technique to overcome this challenge. The as-prepared materials are analyzed for crystallinity, morphology, and chemical bonding through X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), high resolution transmission electron spectroscopy (HRTEM), and Fourier transform infrared (FTIR) spectroscopy, respectively. The optimized electrocatalyst reveals higher electrochemical performance for OER with an overpotential value of 262 mV at 10 mA/cm2 current density, Tafel slope value of 59 mV/dec, and charge transfer resistance (Rct) of 72 Ω. Moreover, the electrochemical active surface area (ECSA) is calculated as 320 cm2. Notably, the desired electrocatalyst shows the stability of 50 h at 10 and 20 mA/cm2 current densities. The as-prepared catalyst (Co3O4@ZnO) with effective electrochemical features can be a potential candidate for energy conversion applications toward a sustainable society.