Structure of hollow carbon nanocapsules synthesized by resistive heating

Nanometer-sized hollow carbon nanocapsules (NCs) were synthesized from amorphous carbon whiskers by resistive heating inside a transmission electron microscope. The structures of NCs were investigated in situ by high-resolution transmission electron microscopy. The number of atomic wall layers ranged from 1 to 5 with 2 being the most frequent number, showing that double-walled NCs were the most stable. The outer diameter of the NCs was in the range from 3 to 9 nm with an average of 5.3 nm. Most NCs showed polyhedral shapes. The interlayer spacing of the NCs reached 0.42 ± 0.05 nm as the number of wall layers decreased.