Carboxylated graphene oxide–Mn2O3 nanorod composites for their electrochemical characteristics

Abstract

Carboxylated-graphene–Mn₂O₃ (G-COOMn) nanocomposites were grown as Mn₂O₃ nanowires on graphene sheets by a one-step thermal method using graphene oxide–COOH (G-COOH) and Mn(NO₃)₂. Graphene oxide (G) was prepared by the Hummers method by using graphite flakes as a starting material. G-COOH sheets were synthesized using G and chloroacetic acid (Cl–CH₂–COOH). G, G-COOH, and G-COOMn were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, ¹³C-nuclear magnetic resonance, and Raman spectroscopy. The electrochemical properties of the fabricated G-COOMn supercapacitor were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge tests. The obtained results showed that the asymmetric supercapacitor had electrochemical capacitance performance within the potential range 0–0.7 V. The supercapacitor delivered a specific capacitance of ∼300 F g⁻¹ at a current density of 50 mA cm⁻². The method used in this work provides an easy and straightforward approach for depositing Mn₂O₃ nanowires on graphene sheets and may be readily extended to the preparation of other classes of hybrids based on G sheets for use in specific technological applications.