3d Transition Metals and Oxides within Carbon Nanotubes by Co-Pyrolysis of Metallocene & Camphor: High Filling Efficiency and Self-Organized Structures

摘要

We demonstrate that a single zone furnace with a modified synthesis chamberdesign is sufficient to obtain metal (Fe, Co or Ni) filled carbon nanotubes(CNT) with high filling efficiency and controlled morphology. Samples areformed by pyrolysis of metallocenes, a synthesis technique that otherwiserequires a dual zone furnace. Respective metallocene in all three cases aresublimed in powder form, a crucial factor for obtaining high fillingefficiency. While Fe@CNT is routinely produced using this technique,well-formed Ni@CNT or Co@CNT samples are reported for the first time. This isachieved by sublimation of nickelocene (or cobaltocene) in combination with'camphor'. These samples exhibit some of the highest saturation magnetization(Ms) values, at least an order of magnitude higher than that reported for Ni orCo filled CNT, by aerosol assisted pyrolysis. The results also elucidate on whyNi or Co@CNT are relatively difficult to obtain by pyrolyzing powdermetallocene alone. Overall, a systematic variation of synthesis parametersprovides insights for obtaining narrow length and diameter distribution andreduced residue particles outside filled CNT - factors which are important fordevice related applications. Finally, the utility of this technique isdemonstrated by obtaining highly aligned forest of Fe2O3@CNT, wherein Fe2O3 isa functional magnetic oxide relevant to spintronics and battery applications.