T. Edison, R. Atchudan, M. G. Sethuraman
Nov 1, 2016
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Journal
Journal of The Taiwan Institute of Chemical Engineers
Abstract
Abstract Carbon supported cobalt oxide nanoparticles (Co 3 O 4 @C NPs) were synthesized by simple thermolysis of cobalt(II) acetate tetrahydrate and Terminalia chebula ( T. chebula ) fruit. The synthesized Co 3 O 4 @C NPs were characterized using attenuated total reflection conjunction with Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) techniques. The specific surface area of Co 3 O 4 @C NPs was measured by N 2 adsorption–desorption isotherm. The ATR-FTIR analysis revealed that the phytoconstituents of T. chebula were carbonized and supports the Co 3 O 4 NPs. The synthesized Co 3 O 4 @C NPs were highly crystalline with carbon support, exposed by the XRD patterns. As inferred from microscopic images, the particle size of Co 3 O 4 @C NPs is in the range of 15–25 nm with distorted spherical shape. The EDS results confirmed the presence of three major elements such as Co, O and C in the synthesized Co 3 O 4 @C NPs. The calculated specific surface area of Co 3 O 4 NPs is 22 m 2 /g. The supercapacitor performance of synthesized Co 3 O 4 @C NPs in 2 M aqueous KOH was analyzed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) methods. The Co 3 O 4 @C NPs showed a maximum specific capacitance of about 642 F/g at 1 A/g of discharging current density between 0 and 0.50 V ( vs . Ag/AgCl). The high specific capacitance of Co 3 O 4 @C NPs could be attributed to the combination of both double layer capacitance and pseudocapacitance.