One-dimensional chain Fe3O4 nanoparticles encapsulated in worm-shaped carbon shell

Chain Fe3O4 nanoparticles encapsulated in worm-shaped carbon shell (defined as “WCCIOs”) were in situ synthesized by copyrolysis of polyethylene, malated-polypropylene and ferrocene in the presence of 10 ml H2O in an autoclave at 700 ∘C for 12 h. The shell thicknesses of these WCCIOs are about 180 nm and the lengths reach up to several micrometers. And the average size of the Fe3O4 nanoparticles inside the worm-shaped carbon shell is about 100 nm. The shapes and compositions of WCCIOs were simply controlled by adjusting the reaction temperatures and relative amounts of the precursors. On the basis of the experimental results, the formation process of the WCCIOs is discussed. The WCCIOs possess well acid resistance, which differs from those reported previously: the nanoparticles were embedded inside the thicker carbon shell. It is also found that the coercivity (Hc) value of the WCCIOs is much higher than that of bare Fe3O4 nanoparticles and bulk Fe3O4.