Ex Situ X-ray Diffraction, X-ray Absorption Near Edge Structure, Electron Spin Resonance, and Transmission Electron Microscopy Study of the Hydrothermal Crystallization of Vanadium Oxide Nanotubes: An

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• 作者：Maguy Jaber ; Fran莽ois Ribot ; Laurent Binet ; Val茅rie Briois ; Sophie Cassaignon ; K. J. Rao ; Jacques Livage ; Nathalie Steunou
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 29, 2012
• 年：2012
• 卷：116
• 期：47
• 页码：25126-25136
• 全文大小：541K
• 年卷期：v.116,no.47(November 29, 2012)
• ISSN：1932-7455

文摘

The nucleation and growth of vanadium oxide nanotubes (VO_x-NT) have been followed by a combination of numerous ex situ techniques along the hydrothermal process. Intermediate solid phases extracted at different reaction times have been characterized by powder X-ray diffraction, scanning and transmission electron microscopy, electron spin resonance, and V鈥揔 edge X-ray absorption near-edge structure spectroscopy. The supernatant vanadate solutions extracted during the hydrothermal treatment have been studied by liquid ⁵¹V NMR and flame spectroscopy. For short durations of the hydrothermal synthesis, the initial V₂O₅-surfactant intercalate is progressively transformed into VO_x-NT whose crystallization starts to be detected after a hydrothermal treatment of 24 h. Upon heating from 24 h to 7 days, VO_x-NT are obtained in larger amount and with an improved crystallinity. The detection of soluble amines and cyclic metavanadate [V₄O₁₂]^{4鈥?/sup> in the supernatant solution along the hydrothermal process suggests that VO_x-NT result from a dissolution鈥損recipitation mechanism. Metavanadate species [V₄O₁₂]4鈥?/sup> could behave as molecular precursors in the polymerization reactions leading to VO_x-NT.}