Phyto-assisted synthesis of cobalt oxide nanoparticles using Terminalia arjuna bark for efficient supercapacitor electrode applications
摘要
With the growing demand for sustainable and efficient energy storage technologies, eco-friendly approaches to synthesize advanced electrode materials are gaining significant attention. In the present work, cobalt oxide (Co₃O₄) nanoparticles (NPs) were synthesized via a green, phyto-assisted method using Terminalia arjuna bark extract as a natural reducing and stabilizing agent. The structural, morphological, and chemical characteristics of the biosynthesized Co₃O₄ NPs were analyzed using UV–Visible spectroscopy, SEM, XRD, FTIR, Raman spectroscopy, XPS, TGA and DTA. UV absorption bands in the region of 200–350 nm indicated the formation of nanoparticles. The crystalline nature of synthesized nanoparticles with the crystallite size of 28–68 nm is confirmed by XRD results. SEM images indicated the quasi- spherical morphology of synthesized Co₃O₄ nanoparticles. Raman peak observed at about 476 cm− 1 is suggestive of crystalline phase of Co₃O₄ NPs. Electrochemical performance and cycling stability of the Co₃O₄ NPs-based electrodes were assessed using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) in varying concentrations of aqueous KOH electrolyte. The electrodes demonstrated a maximum specific capacitance of 77 F/g at a scan rate of 2 mV/s within a potential window of 0.8 V using 20 M KOH, confirming their potential as cost-effective and environmentally benign candidates for supercapacitor applications.