Synthesis and study of electrochemical, optical, and magnetic properties of Fe3O4/MWCNT-COOH nanocomposite

Fabrication of MWCNTs-based magnetic composites is an effective approach to improve the specific capacitance of supercapacitors. Current magnetic composite design strategies are mainly based on magnetic material tuning, while the influence of MWCNTs structure on supercapacitor performance is still unclear. In this report, Fe3O4 nanoparticles and Fe3O4/MWCNT-COOH nanocomposite have been prepared by electrochemical technique. XRD, FTIR, TGA and Raman analysis characterized the synthesized nanoparticles. SEM images showed that MWCNTs are wrapped around the spherical Fe3O4 nanoparticles to form a three-dimensional interconnected network. The AFM analysis confirmed that the surface roughness of the Fe3O4/MWCNT-COOH composite is higher than that of Fe3O4 NPs. The grain size obtained from SEM and AFM images showed that the Fe3O4/MWCNT-COOH composite has a larger grain size than Fe3O4 NPs. In addition, the optical and magnetic properties of nanoparticles were investigated by UV-visible spectrophotometer and vibrating sample magnetometer (VSM), respectively. The optical band gap, saturation magnetization (Ms), remanent magnetization (Mr) and intrinsic coercivity (Hc) decreased with incorporating the MWCNT-COOH into the matrix of Fe3O4 NPs. An electrochemical approach was used to fabricate Fe3O4/MWCNT-COOH on nickel foam for cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) measurements.