Oxidative properties of carbon nanocapsules encapsulated with lanthanum carbide

Yamamoto, Kazunori; Wakahara, Takatsugu*; Akasaka, Takeshi*

There has been great interest in the incorporation of foreign materials into fullerene-like carbon structures. Nanocapsules filled with LaC crystallites were discovered in carbonaceous cathode deposits grown by arc discharge. Although rare-earth carbides are hygroscopic and readily hydrolyze in moist air, the carbides in the capsules did not degrade even after a decade of exposure. Moreover, empty nanocapsules are more resistant to oxidation than other forms of carbon (such as diamond, soot, graphite, and C). Therefore higher oxidation resistance is also expected for the filled nanocapsules. In this study protective nature of the outer graphitic cages of stuffed nanocapsules was demonstrated. Nanocapsules stuffed with LaC were heated in thermogravimetric analyser in excess air. The observation showed that all carbon nanocapsules including filled and empty nanocapsules seen in the sample were completely changed, suggesting degradation of nanocapsules at 580C.