Radial growth kinetics of epitaxial pyrolytic carbon layers deposited on carbon nanotube surfaces by non-catalytic pyrolysis

Chemical vapor deposition of pyrolytic carbon (PyC) onto nanotube (CNT) surfaces by hydrocarbon pyrolysis can thicken the diameter until desirable size. Vapor-induced thickening CNTs may require no metal catalysts because CNT-templated growth easily convert PyC deposits into epitaxial graphene shells. However, little work has been done on kinetics vapor-induced CNT process during non-catalytic pyrolysis. In this study, we discuss mechanism layers achieved low-pressure (≤1.5 kPa) ethylene, which is distinct from previous studies using much higher gas pressures (4–100 for deposition. The average thickness deposited calculated analyzing transmission electron microscopy images PyC-coated CNTs. crystallinity evaluated Raman spectroscopy and X-ray diffraction. be adjusted simply changing time under typical parameters (800 °C-1.5 kPa ethylene). We find a two-stage nonlinear behavior to describe layers, indicating that radial rate influenced number surface active sites. This study reveals self-assembly graphitic template, expected promote diameter-controlled synthesis