The effect of apple pectin agent on the structural, magnetic, and optical properties of cobalt ferrite nanoparticles synthesized by the auto-combustion sol-gel method

Abstract

In this investigation, in order to enhance the properties of cobalt ferrite magnetic nanoparticles, apple pectin was utilized as a natural additive during the sol-gel auto-combustion technique. Differential thermal analysis (DTA) and thermogravimetric (TGA) curves revealed that the initial temperature of the combustion process drops when apple pectin is present, indicating that this additive improves combustion conditions. The X-ray diffraction (XRD) patterns demonstrated that a cubic spinel structure of pure cobalt ferrite nanoparticles was formed in the presence of apple pectin without the existence of a secondary phase. Additionally, the structural parameters, including the lattice parameters, average crystallite size, and cation distribution between the tetrahedral and octahedral sites, were determined using the Rietveld refinement method. All the synthesized samples exhibited a mixed spinel structure based on the investigation of the cation distribution. A decrease in particle size and nanoparticle agglomeration was observed using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Moreover, the magnetic properties were investigated. According to the experimental findings, the presence of 0.3 g apple pectin increased the saturation/remanence magnetization and coercivity of cobalt ferrite nanoparticles. The improvement in magnetic properties was correlated with the average crystallite size, cation distribution, and magnetic moment of the cations occupying the octahedral/tetrahedral sites. In addition, the diffuse reflectance spectroscopy (UV–Vis-DRS) results showed that the energy of the band gap varies from 1.54 to 2.21 eV in the synthesized samples.