Nano-structured carbon obtained by chlorination of NbC

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• 作者：D. Á ; vila-Brande ; N.A. Katcho ; E. Urones-Garrote ; A. Gó ; mez-Herrero ; A.R. Landa-Cá ; novas and L.C. Otero-Dí ; az
• 关键词：Chemical treatment ; Electron microscopy ; Electron energy loss spectroscopy ; Microstructure ; Surface areas
• 刊名：Carbon
• 出版年：2006
• 出版时间：April 2006
• 年：2006
• 卷：44
• 期：4
• 页码：753-761
• 全文大小：789 K

文摘

New carbon materials have been synthesized by chlorinating niobium carbide at different temperatures. During the reaction, the volatile niobium chloride, mainly NbCl₅, is formed and eliminated leaving the carbon in the shape of spherical particles. TEM examination of the remaining particles revealed that at 400 °C and 700 °C they are composed of a NbC core with an amorphous carbon shell outside. The NbC cores are very small (20 nm) at 700 °C and they are not observed at 900 °C. Carbon particles without the NbC core present a more ordered structure composed of concentric wavy graphene layers. This structure seems intermediate between carbon onions and carbon blacks. The 900 °C sample presents a very high BET surface area (1292 m² g⁻¹) and the lower temperature samples exhibit a hysteresis phenomenon that can be attributed to the existence of large pores in the interspace between the NbC core and the carbon shell.