Impulse Heating an Intercalated Compound Using a 27.12 MHz Atmospheric Inductively Coupled Argon Plasma to Produce Nanotubular Structures

Conclusions

We have shown that impulse heating a covalently intercalated compound in inert gas environment yields closed nanotube structures in the exfoliated graphite. Treated with FeCl₃ and reheated, open nanotubular and nanoencapsulated structures are identified by TEM. This opens an exciting area of research in that a variety of intercalated compounds could be tested as precursors and several metals (Ni, Co, etc.) could be examined in the heating stage. The impulse heating of intercalated nonmetal compounds to produce nanotubular structures could also be extended to the carbon arc and laser ablation techniques.

From past work with carbon arcs, parameters such as gas pressure, voltage, current density and electrode gap were optimized to maximize fullerene and nanotube production. Other techniques have conditions that need to be optimized to produce certain types of spherical (C₆₀, C₇₀, etc.) or tubular allotropes (single wall, multi-wall, etc.) of carbon. This work shows that two other parameters, carbon hybridization (sp ² vs. sp³) and the distance between graphite layers in the starting material, can also be influential in the production of certain nanoscale structures.