Carbon nanotubes/magnetite hybrids prepared by a facile synthesis process and their magnetic properties

Abstract

In this paper, a facile synthesis process is proposed to prepare multi-walled carbon nanotubes/magnetite (MWCNTs/Fe 3 O 4 ) hybrids. The process involves two steps: 1) water-soluble CNTs are synthesized by one-pot modification using potassium persulfate (KPS) as oxidant. 2) Fe 3 O 4 is assembled along the treated CNTs by employing a facile hydrothermal process with the presence of hydrazine hydrate as the mineralizer. The treated CNTs can be easily dispersed in aqueous solvent. Moreover, X-ray photoelectron spectroscopy (XPS) analysis reveals that several functional groups such as potassium carboxylate (-COOK), carbonyl (-C=O) and hydroxyl (-C-OH) groups are formed on the nanotube surfaces. The MWCNTs/Fe 3 O 4 hybrids are characterized with respect to crystal structure, morphology, element composition and magnetic property by x-ray diffraction (XRD), transmission electron microscopy (TEM), XPS and superconducting quantum interference device (SQUID) magnetometer. XRD and TEM results show that the Fe 3 O 4 nanoparticles with diameter in the range of 20-60 nm were firmly assembled on the nanotube surface. The magnetic property investigation indicated that the CNTs/Fe 3 O 4 hybrids exhibit a ferromagnetic behavior and possess a saturation magnetization of 32.2 emu/g. Further investigation indicates that the size of assembled Fe 3 O 4 nanoparticles can be turned by varying experiment factors. Moreover, a probable growth mechanism for the preparation of CNTs/Fe 3 O 4 hybrids was discussed.

Controlling the size and size distribution of magnetite nanoparticles on carbon nanotubes

“…After the addition of the ethanol solution of Fe(NO 3 ) 3 , ferric ions reacted with oleate to form ferric oleate which were then attached onto the surface of CNTs [6]. Besides, some ferric ions were attached on the CNTs through the functional groups, such as carboxylic groups (-COOH) [28]. Subsequently, the ferric ions were in situ reduced into Fe 3 O 4 by EG with the assistance of sodium oleate [29].…”

Mechanistic studies on the formation of silver nanowires by a hydrothermal method

“…Fig. 8c shows the C 1s XPS spectrum of the Ag nanowire prepared at 160°C for 24 h. The peak was deconvoluted into four individual components assigned to C 1s of CAC or C@C (284.5 eV), CAO (286.2 eV), C@O (287.6 eV), and O@CAO (288.9 eV) [31][32][33]. Reflecting the existence of some hydrophilic groups, the Ag nanowires in this study were easily dispersed in water or alcohol due to the affinity of the wires for these solvents, while the wire immediately coagulated in toluene.…”

Facile synthesis and magnetic properties of monodisperse Fe3O4/silica nanocomposite microspheres with embedded structures via a direct solution-based route

“…Examples of the preparation of magnetic polymer microspheres, magnetic natural macromolecule microspheres, and magnetic silica microspheres have been well established [23][24][25][26][27]. Among which, silica is generally employed as coating material over the surface of metal oxide nanoparticles for its desirable properties including high stability against aggregation, exceptional stability of aqueous dispersions, chemically inert, easy surface modification, strong magnetic susceptibility, and minimal residual magnetism, as well as easy control of interparticle interactions and biocompatibility in biological systems [28][29][30][31][32][33][34][35][36][37]44].…”