Beading of cobalt substituted nickel ferrite nanoparticles on the surface of carbon nanotubes: a study of their synthesis mechanism, structure, magnetic, optical and their application as photocatalyst.

Cobalt doped nickel ferrite nanoparticles were successfully loaded on the surface of carbon nanotubes using microemulsion method. In this method, carboxylic group functionalized carbon nanotubes were made to act as a solid support for the beading of ferrite nanoparticles. Sodium dodecyl sulfate was used as a soft template for controlling the shape of nanoparticles. The ferrite/CNTs nanocomposite formation was confirmed using powder X-Ray Diffraction (XRD) and Fourier Transform Infrared (FT-IR) spectroscopy. High Resolution Transmission Electron Microscope (HR-TEM) was used to scrutinize the different synthetic stages of ferrite/CNTs nanocomposites. Magnetic studies of Ni1-xCoxFe2O4/MWCNTs were carried out using Vibrating Sample Magnetometer (VSM) where all the samples exhibited ferromagnetic behavior. The saturation magnetization increased with increasing concentration of cobalt ion, attributed to the higher magnetic moment of cobalt ions as compared to nickel ions. The photo-catalytic activity of ferrite/CNT nano-composites was also studied for the photo-degradation of Rhodamine B (RhB) dye under visible- light irradiation. The dye degradation occurred in 15-25 min in the presence of various ferrite/CNT composites. In addition, the photo-catalytic activity of ferrites was found to enhance in the presence of CNTs, as compared to pristine ferrites.