Preparation, Characterization, Electrochemical And Magnetic Properties Of One-dimensional FeNi/CNTs Nanocomposite

An advanced research field of physics, chemistry, material science and other sciences—the fillings and coatings of carbon nanotubes have become the research focus of carbon-based function materials. Although it has been reported about the filling or coating of carbon nanotubes with monometal (or metal oxides), it is only our group to do attempting work for metal alloy nanoparticles to fill or coat carbon nanotubes via wet chemistry. In the paper FeNi alloy nanoparticles were filled in and coated on carbon nanotubes using carbon nanotubes as templates via wet chemistry. One-dimensional FeNi/CNTs nanocomposites with controlled composition and controlled size were prepared, which were characterized with FT-IR, XRD, TEM, HRTEM, SAED and EDX. The electrochemical and magnetic properties were studied. The mainly work as followed: 1. The refilling of carbon nanotubes was discussed through measuring the surface tension and capillary action of mixed metallic salts, the dense degree of FeNi alloy nanoparticles inside carbon nanotubes increased and the yield of filling increased. 2. The Fe_1-xNi_x alloy nanoparticles with controlled composition and controlled size were coated on carbon nanotubes via wet chemistry firstly. Controlling the composition of mixed metal salts and synthetic conditions controlled the composition of Fe_1-XNi_X alloy nanoparticles. When X=0.25, the FCC structure and BCC structure coexist obviously, while when X=0.50, 0.75, most of Fe_1-xNi_x alloy nanoparticles have FCC structure. The grain size decreased with the increase of Ni concentration. FeNi alloy nanoparticles'size was controlled through controlling the molar ratio of mixed metallic salts to carbon nanotubes. When the molar ratio changed from 2 molar % to 12 molar %, the size of nanoparticles increased, while the molar ratio changed from 12 molar % to 25 molar %, the size of nanoparticles decreased. The formation mechanism of FeNi alloy nanoparticles was discussed. 3. One-dimensional FeNi/CNTs nanocomposites have obvious electrocatalytic capability. The electrochemical process is an irreversible process by electrochemistry-controlled process. The proton joins the electrochemical process, which is maybe an electrochemical process with one proton and two electrons translated. The electrocatalytic capability of FeNi/CNTs nanocomposites decreased with the increase of the Ni concentration. 4. The relationships between the composition, structure, size of FeNi alloy nanoparticles and magnetic properties were discussed. The coercivity of Fe_1-XNi_X alloy nanoparticles decreased with the decrease of grain size. When x=0.50, the saturation magnetization have minimum value, which is maybe related to FCC and BCC structure of nanoparticles. The coercivity and the saturation magnetization of FeNi/CNTs nanocomposites with different molar ratio decreased with the decrease of nanoparticles size.