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胡征, Yajun Tian, Zheng Hu, *, Yong Yang, Xizhang Wang, Xin Chen, Hua Xu, Qiang Wu, Weijie Ji, and Yi Chen
1182 J. AM. CHEM. SOC. 9 VOL. 126, NO.4, 2004,-0001,():
-1年11月30日
By using the in situ thermal analysis-mass spectroscopic technique, combined with transmission electron microscopic characterization of the carbon nanotube (CNT) product, we have studied the chemical vapor deposition (CVD) growth of CNTs with Fe-Co/Á-Al2O3 catalyst and benzene precursor in the range of room temperature to 700℃. The growth process has been clearly illuminated, which starts from the reduction of catalyst around 645℃ followed by the dissociation of carbon-hydrogen bonds of benzene and the sequential growth of CNTs. A surprising fact is that no possible hydrocarbon species derived from benzene was detected, indicating that the carbon-carbon bond was not broken under our experimental conditions. All of the experimental results strongly reinforce the six-membered-ring-based growth model, and a schematic elucidation is presented accordingly. This in situ study not only reveals the unique and convincing information directly related to the growth mechanism from the involved chemistry, but also provides a powerful way to clarify the mechanism of CVD synthesis of CNTs with other precursors.
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胡征, K.F. Huo, Z. Hu, *, J.J. Fu, H. Xu, X.Z. Wang, and Y. Chen Y.N. Lu
J. Phys. Chem. B, Vol. 107, No.41, 2003 11317,-0001,():
-1年11月30日
Periodic spindle-unit boron nitride (BN) nanotubes with buglelike open-end tips have been found in the product by nitriding Fe-B nanoparticles at 1100℃ with a mixture of nitrogen and ammonia gas. The microstructure was well-characterized by high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (EDX). The diameter of this BN nanotube shows a decreasing tendency along the growth direction. For each spindle unit, the outer diameter decreases steeply and then increases gradually, accompanied by thinning of the wall thickness along the growth direction. Some spindle units are partially occupied by the iron-containing catalyst particles at the hemispherical-like ends. An improved stress-induced sequential growth model has been reasonably deduced accordingly, with which the formation process of this novel BN nanostructure could be well understood.
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【期刊论文】Boron Nitride Nanocages Synthesized by a Moderate Thermochemical Approach**
胡征, Yi Pan, Kaifu Huo, Yemin Hu, Jijiang Fu, Yinong Lu, Zhendong Dai, Zheng Hu, * and Yi Chen
small 2005, 1, No.12, 1199-1203,-0001,():
-1年11月30日
boron
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胡征, Hua Xu, Jing Ma, *, Xin Chen, Zheng Hu, Kaifu Huo, and Yi Chen
J. Phys. Chem. B, Vol. 108, No.13, 2004 4025,-0001,():
-1年11月30日
A possible smallest single-walled BN nanotube with the diameter of 0.4nm is proposed. The studied nanotube is of armchair (3,3) and thought to be associated with the BN fullerene, B12N12. We have applied the ab initio MP2/6-31G//HF/6-31G method to investigate the growth mechanisms of this nanotube from B12N12. Our results show that a B12N12 fullerene may react with B2H6 and NH3 to form an armchair (3,3) tubular structure under certain experimental conditions such as high temperature. The armchair (3,3) tube can continuously incorporate B and N atoms to grow and can also disassociate H2 to close into a half-B12N12 cap. The growth of the tube is predicted to be favorable to the capping of the tube in an atmosphere with B2H6 and NH3 in it. And the cap of the tube is relatively easier to be opened by H2 or B2H6 and NH3 to convert to a growing open-ended tube.
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【期刊论文】AlN Nanotube: Round or Faceted?
胡征, Xin Chen, †, Jing Ma, *, ‡, Zheng Hu, Qiang Wu, † and Yi Chen†
,-0001,():
-1年11月30日
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