Graphite-like carbon-encapsulated iron nanoparticle self-assembly into macroscopic microtube structures

Abstract

We report the self-assembly of graphite-like carbon-encapsulated iron nanoparticles into macroscopic microtube structures by using a floating catalytic chemical vapor deposition method. The microtubes have a hollow tubular architecture with a diameter of several tens of microns, and several are up to ten centimetres in length. The walls of the microtubes are formed by aggregation of graphite-like carbon-encapsulated iron nanoparticle building blocks generated from catalytic pyrolysis of toluene and the wall thickness is several microns. The microtubes combining the tubular geometry with nanoparticle morphology and properties are constructed by self-assembly of graphite-like carbon-encapsulated iron nanoparticles induced by anisotropic particle mutual interactions. This unusual carbon-capsulated iron nanoparticle tubular superstructure provides spatially distributed nucleation sites, which can induce the construction of two dimensional (2D) and 3D carbon nanotube networks with various types of multi-terminal junctions. More generally, we believe that the catalytic approach with spatially distributed nucleation sites for 1D nanomaterials can be readily expanded to create other 1D nanomaterial network structures.