Graphene-Assisted Magnetic Iron Carbide Nanoparticle Growth

Iron carbide nanoparticles (NPs) encapsulated by multilayer graphene, Fe3C@graphene, were produced by one-step chemical vapor deposition (CVD) at high temperature (950 °C) with ferrocene powder as a precursor and a copper foil surface as a catalyst. At high temperature, the ferrocene molecules adsorb dissociatively on copper catalysts, forming a layer of graphene decorated by core–shell Fe3C@graphene NPs. At high temperature, graphene has a low surface energy, allowing the lateral diffusion of iron atoms and carbon fragments to form NPs. The as-prepared core–shell Fe3C@graphene NPs have varying diameter from 50 to 80 nm, while the graphene shells vary from 8 to 40 graphene layers. The results demonstrate that the thickness of the graphene shell growth for NPs increases with increasing reaction time from 1 to 7 h. Graphene-assisted NP growth allows the formation of uniform core–shell Fe3C@graphene particles rather than carbon nanotube formation. The synthesized NPs were analyzed via different surface-sensitive techniques and magnetic measurement methods to determine their structural and magnetic properties. Our work provides a rapid and general procedure for core–shell Fe3C@graphene synthesis by using a CVD technique.