In:
Chemistry – A European Journal, Wiley, Vol. 13, No. 11 ( 2007-04-05), p. 3234-3240
Abstract:
The effects of both organically modified montmorillonite (OMMT) and Ni 2 O 3 on the carbonization of polypropylene (PP) during pyrolysis were investigated. The results from TEM and Raman spectroscopy showed that the carbonized products of PP were mainly multiwalled carbon nanotubes (MWNTs). Surprisingly, a combination of OMMT and Ni 2 O 3 led to high‐yield formation of MWNTs. X‐ray powder diffraction (XRD) and GC–MS were used to investigate the mechanism of this combination for the high‐yield formation of MWNTs from PP. Brønsted acid sites were created in degraded OMMT layers by thermal decomposition of the modifiers. The resultant carbenium ions play an important role in the carbonization of PP and the formation of MWNTs. The degradation of PP was induced by the presence of carbenium ions to form predominantly products with lower carbon numbers that could be easily catalyzed by the nickel catalyst for the growth of MWNTs. Furthermore, carbenium ions are active intermediates that promote the growth of MWNTs from the degradation products with higher carbon numbers through hydride‐transfer reactions. The XRD measurements showed that Ni 2 O 3 was reduced into metallic nickel (Ni) in situ to afford the active sites for the growth of MWNTs.
Type of Medium:
Online Resource
ISSN:
0947-6539
,
1521-3765
DOI:
10.1002/chem.200601018
Language:
English
Publisher:
Wiley
Publication Date:
2007
detail.hit.zdb_id:
1478547-X
