Fast Rate Growth of Organized Carbon Nanotubes by CVD Using Iron Pentacarbonyl as Gas‐Phase Catalyst

Abstract

Organized carbon nanotubes (CNTs) have been grown at a fast rate by a gas-phase, catalytic CVD technique at 600-750°C for 15 min with the iron pentacarbonyl/acetylene/hydrogen system. The CNT growth at various temperatures and flow rates of iron pentacarbonyl, acetylene, and hydrogen, has been quantitatively analyzed by its length. The CNT growth accelerates with growth temperatures up to 700°C, but depends upon growth conditions at 750°C. Acetylene at a higher input deactivates catalysts owing to its supersaturated carbon content, approaching that of Fe 3 C. The deactivation of catalysts can be overcome by the addition of hydrogen via a hydrocarbon reaction to refresh the poisoned catalysts or by the high input of iron pentacarbonyl to provide fresh catalysts for the continuous CNT growth. CNTs with a longest tube length of 845±28 lm and a fastest growth rate of 56±1.9 lm min -1 were obtained. A mixed-mode growth mechanism combining the tip-and basegrowth modes was suggested.

A novel method to produce carbon nanotubes using EDM process

“…While for CVD method, the length of CNTs can achieve 850 mm [16]. Thus, the length of CNTs in this research is not so long as that of CVD method.…”

Carbon Nanotube Fabrication at Industrial Scale

“…In the unsupported catalyst approach, a volatile compound containing the catalytic element [115,116], e.g., Fe (CO) 5 , Fe(C 5 H 5 ) 2 , or Ni(C 5 H 5 ) 2 is used as the catalyst source. The nanotubes form in the vapor phase and condense onto cold surfaces.…”

Critical Role of the Acetylene Content and Fe/C Ratio on the Thickness and Density of Vertically Aligned Carbon Nanotubes Grown at Low Temperature by a One-Step Catalytic Chemical Vapor Deposition Process

“…This one-step CCVD processes enables the constant renewing of the catalyst particles as reported at high temperature (850 °C) by Castro et al [ 40 ]. However, in the literature, very few studies of VACNT synthesis with a single-step method are reported at a low temperature and atmospheric pressure [ 27 , 39 , 41 , 42 , 43 , 44 ]. Unlike two-step processes, here we can assume that particle deactivation will be limited.…”