Graphite-incorporated MoS ₂ nanotubes: A new coaxial binary system

Graphite-filled MoS ₂ nanotubes were synthesized by pyrolizing propylene inside MoS ₂ nanotubes prepared by a template-assisted technique. The large coaxial nanotubes were constituted of graphite sheets inserted between the MoS ₂ layers, forming the outer part, and coaxial multiwall carbon nanotubes intercalated with MoS ₂ inside. High-resolution electron microscopy (HREM) and electron energy loss spectroscopy techniques along with molecular dynamics simulation and quantum mechanical calculations were used to characterize the samples. The one-dimensional structures exhibit diverse morphologies such as long straight and twisted nanotubes with several structural irregularities. The interplanar spacing between the MoS ₂ layers was found to increase from 6.3 to 7.4 Å due to intercalation with carbon. Simulated HREM images revealed the presence of mechanical strains in the carbon-intercalated MoS ₂ layers as the reason for obtaining these twisted nanostructures. The mechanism of formation of carbon-intercalated MoS ₂ tubular structures and their stability and electronic properties are discussed. Our results open up the possibility of using MoS ₂ nanotubes as templates for the synthesis of new one-dimensional binary-phase systems.