Synthesis and characterization of nickel oxide/cobalt oxide nanocomposite for effective degradation of methylene blue and their comparative electrochemical study as electrode material for supercapacitor application

Abstract

In this paper, we have synthesized a nanocomposite of nickel oxide (NiO) and cobalt oxide (Co3O4) using l-ascorbic acid which is named A(NC). Herein, A stands for l-ascorbic acid, N stands for nickel oxide (NiO), and C stands for cobalt oxide (Co3O4). Where l-ascorbic acid has been used as stabilizing agent/capping agent. Herein, a simple two steps wet-chemical method has been used for the synthesis of the nanocomposite A(NC). This synthesized nanocomposite has been characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), UV–visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR). A comparative electrochemical study has been done using cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) techniques for supercapacitor performance. This study has been performed with a three-electrode system using 1 M Na2SO4 as a supporting electrolyte. Herein, a glassy carbon electrode (GCE) as a working electrode, Ag/AgCl as a reference electrode and Pt electrode as a counter electrode have been used in the electrochemical analysis. The CV curves have been recorded at different scan rates of 5 mV/s, 10 mV/s, 15 mV/s, 20 mV/s, 40 mV/s, 80 mV/s, and 100 mV/s respectively. The value of specific capacitance has been calculated 2.1472 F/g at 5 mV/s and energy density at 0.1074 Wh/kg using the CV curves. Whereas, specific capacitance and energy density have been determined 0.6833 F/g and 0.0342 Wh/kg respectively using the GCD method. Also, the photocatalytic degradation behavior of the synthesized nanocomposite A(NC) has been investigated against methylene blue (MB) dye. Herein, 89.88% MB dye has been degraded with synthesized nanocomposite A(NC) within 360 min in the presence of sunlight.