Effect of in-situ growth and separate addition method in hydrothermal process on the structural and magnetic properties of CoNiFe2O4@functionalized CNTs nanocomposite

Multi-walled carbon nanotubes (MWCNT) were synthesized by the chemical vapor deposition method and functionalized successfully through a two-step procedure, namely sonication and acid reflux. Functionalized multi-wall carbon nanotubes (FMWCNT) were decorated with crystalline nickel-substituted cobalt ferrite nanoparticles (CNF) by the two different routes of hydrothermal method to form CNF@FMWCNT nanocomposite. The nanocomposites with different weight ratios of CNF and FMWCNT were characterized by X-ray diffraction analysis (XRD), Transmission electron microscopy (TEM), Raman spectroscopy, Fourier-transform infrared spectra analyzer (FTIR), thermogravimetric analyzer (TGA), and physical property measurement system. The XRD patterns revealed the formation of the cubic phase spinel structure of CNF with the optimized 1:1 weight ratio composite with a crystallite size of 11.55 nm, accordingly the Williamson–Hall (W–H) analysis. TEM confirmed the functionalization of FMWCNT, crystallinity of CNF and better adhesion between ferrite and FMWCNT in FCI11 composite than FCS11. FTIR study confirmed the presence of functional groups in as-synthesized samples. The study of the Raman spectra provided useful information about the quality of MWCNT and its degree of functionalization, and the quality of nanocomposites. TGA study revealed that different nanocomposites were found to have dissimilar thermal stability depending on the different synthesis routes. The magnetic study showed CNF@FMWCNT nanocomposite of 1:1 weight percent composition, produced by in-situ growth method, obtained significant magnetization features among all the samples. Nanocomposites prepared by the in-situ growth method show improved characteristics than the separate addition technique.