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outer diameters of 20 40 nm. The tube length is between (Fig. 4b).
0.5 and 8 mm. Most of the MWCNTs are coiled to In conclusion, the detonation of nitro-containing organic
different extents. Based on the TEM images, it is estimated explosives as common as m-dinitrobenzene can be used to
that the sample contains 30 40% MWCNTs. Higher synthesize CNTs in the presence of a catalyst. The
loading densities of DNB and appropriately higher molar approach is simple, low-cost and universal. From the
ratios of DNB to the metal salt are preferable to yield experimental observation, it is estimated that some other
CNTs-rich products, possibly due to larger heat release nitro-containing organic explosives possessing higher
[12] and slower local heat diffusion, which are very chemical energy than DNB, such as picric acid and
important for the nucleation and thermal annealing of trinitrotoluene, may be more effective for CNTs growth
CNTs [12,13]. In the experiments where DNB loading because their detonations can generate higher tempera-
density is lower than 0.05 g/ml and/or the molar ratio of tures. In addition, a further increase in CNTs selectivity
DNB/metal salt is lower than 1:1, no CNTs are found in and tailoring of structure defects may be available by
the products, carbon-encapsulated metal nanoparticles and elaborate design of detonation experiments.
amorphous carbon particles are the main products.
Fig. 2 is a Raman spectrum of the sample shown in Fig.
1. There are two main peaks in the region between 200 and
Acknowledgements
2000 cm21. The one located at 1595 cm21 (G-band [14])
can be designated as the stretching vibration mode of
The authors thank the National Scientific Foundation of
graphite crystals indicating the formation of graphitized
China for partial support (No. 59872047) and Profs. Bing
CNTs. The one located at 1329 cm21 (D-band [14]) can be
Zhong and Yongwang Li for some valuable discussions.
designated as disorder-induced mode. Kang et al. [15]
attributed the D-band to the carbonaceous particles existing
near CNTs or adhering to the walls of CNTs. The
relatively low intensity of the G-band with respect to that
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