Transformation of silicon nanoparticles on a carbon nanotube heater into hollow graphitic nanocapsules via silicon carbide

• The dynamic behavior of Si nanoparticles on a MWCNT surface at elevated temperatures is revealed.
• The Si nanoparticles react with the outer layers of the MWCNT to form SiC nanoparticles
• The SiC nanoparticles on the MWCNT thermally decompose to generate carbon nanocapsules at a temperature less than 1900 K.

The changes in the structure and composition of silicon (Si) nanoparticles supported on a multiwall carbon nanotube (MWCNT) during Joule heating of the MWCNT were studied by in situ high-resolution transmission electron microscopy. The Si nanoparticles reacted with the outer layers of the MWCNT to form silicon carbide (SiC) nanoparticles with increasing temperature. At temperatures of up to approximately 1900 K, silicon atoms were entirely sublimated from the SiC nanoparticles, and the remaining carbon atoms formed hollow carbon nanocapsules consisting of multilayered graphene shells on the MWCNT.