Multiwalled carbon nanotubes (MWCNT) are synthesized by isobutane decomposition at 700 °C over aspurchased and iron-loaded K10-montmorillonite catalysts. The results show that, upon reduction at 500 °C, K10 catalyzes isobutane decomposition. Few carbon fibers accompany the prevailing carbon flakes formation. Upon Na+ exchange or by increasing the reduction temperature, the activity of the clay decreases. Fe-K10 behaves as a bifunctional catalyst: on added metal sites, MWCNT preferentially form, while on the support, carbon flake formation mainly occurs. At a given metal load, the increase of the reduction temperature up to 700 °C or the use of Na+-exchanged K10 as a support generally leads to an enhancement of the selectivity to MWCNT, because of the diminishing of the support active sites. Under the present reaction conditions, Fe supported on Na+ exchanged K10 are the most active among the investigated catalysts. MWCNT copiously form, both at low and high metal load, and exhibit the highest structural order.
Titolo: | K10 Montmorillonite Based Catalysts for the Growth of Multiwalled Carbon Nanotubes through Catalytic Chemical Vapor Deposition |
Autori: | |
Data di pubblicazione: | 2010 |
Rivista: | |
Handle: | http://hdl.handle.net/20.500.12318/87 |
Appare nelle tipologie: | 1.1 Articolo in rivista |