In Situ Synthesis, Magnetic Property, and Formation Mechanism of Fe 3 O 4 Particles Encapsulated in 1D Bamboo-Shaped Carbon Microtubes

Fe3O4 particles embedded in bamboo-shaped carbon microtubes (defined as "BCIOs") with ferromagnetic properties were in situ produced by redox reactions between ferrocene and glycerol in a stainless steel autoclave of 20-mL capacity at 600 degrees C; these BCIOs have wide and periodic variable outer diameter distributions and have lengths up to tens of micrometers. It is found that their coercivity values were in inverse ratio with the sizes of interior Fe3O4 particles when compared with the previous reports. After the acid treatment process, bamboo-shaped carbon microtubes could also be obtained, while when a contrasting experiment was carried out in a stainless steel autoclave of 60-mL capacity, only irregular-shaped Fe3O4 particles encapsulated in carbon capsule core-shell composites were produced. On the basis of the experimental results, the possible formation processes of these as-obtained products were discussed.