A facile controlled in-situ synthesis of monodisperse magnetic carbon nanotubes nanocomposites using water-ethylene glycol mixed solvents

In this paper, a facile and controllable method for in-situ synthesis of the magnetic carbon nanotubes nanocomposites (Fe/CNTs) in water-ethylene glycol (EG) mixed solvents is reported by the deposition-precipitation method following annealing. The effect of water/EG ratio on the physico-chemical properties of magnetic Fe/CNTs is investigated by X-ray diffraction, transmission electron microscope, scanning electron microscopy, thermogravimetric analysis and physical property measurement system. The results indicate that the iron particle size distribution and grain size can be well-tuned by adjusting the water/EG ratio. With the variation of EG fraction in the mixed solvent, the nucleation, growth and crystallization of magnetic iron oxides with a controllable morphologies and particle sizes attached on the exterior surface of CNTs can be achieved. The as-prepared Fe/CNTs nanocomposites display superparamagnetic property at room temperature and the water/EG ratio determines the magnetization of the sample. Possible formation mechanism for magnetic Fe/CNTs is proposed based on the characterization results.