The synergistic effect in the Fe-Co bimetallic catalyst system for the growth of carbon nanotube forests

We report the growth of multi-walled carbon nanotube forests employing an active-active bimetallic Fe-Co catalyst. Using this catalyst system, we observe a synergistic effect by which-in comparison to pure Fe or Co-the height of the forests increases significantly. The homogeneity in the as-grown nanotubes is also improved. By both energy dispersive spectroscopy and in-situ x-ray photoelectron spectroscopy, we show that the catalyst particles consist of Fe and Co, and this dramatically increases the growth rate of the tubes. Bimetallic catalysts are thus potentially useful for synthesising nanotube forests more efficiently. (C) 2015 AIP Publishing LLC.