Nguyen Cattien V, Delziet Lance, Matthews Kristopher, Chen Bin, Meyyappan M
NASA Ames Research Center, Moffett Field, California, USA.
J Nanosci Nanotechnol. 2003 Feb-Apr;3(1-2):121-5. doi: 10.1166/jnn.2003.178.
Individual, free-standing, vertically aligned multiwall carbon nanotubes or nanofibers are ideal for sensor and electrode applications. Our plasma-enhanced chemical vapor deposition techniques for producing free-standing and vertically aligned carbon nanofibers use catalyst particles at the tip of the fiber. Here we present a simple purification process for the removal of iron catalyst particles at the tip of vertically aligned carbon nanofibers derived by plasma-enhanced chemical vapor deposition. The first step involves thermal oxidation in air, at temperatures of 200-400 degrees C, resulting in the physical swelling of the iron particles from the formation of iron oxide. Subsequently, the complete removal of the iron oxide particles is achieved with diluted acid (12% HCl). The purification process appears to be very efficient at removing all of the iron catalyst particles. Electron microscopy images and Raman spectroscopy data indicate that the purification process does not damage the graphitic structure of the nanotubes.
独立的、垂直排列的多壁碳纳米管或纳米纤维非常适合用于传感器和电极应用。我们用于制备独立且垂直排列的碳纳米纤维的等离子体增强化学气相沉积技术，在纤维尖端使用催化剂颗粒。在此，我们展示了一种简单的纯化工艺，用于去除通过等离子体增强化学气相沉积得到的垂直排列碳纳米纤维尖端的铁催化剂颗粒。第一步是在200 - 400摄氏度的空气中进行热氧化，这会导致铁颗粒因形成氧化铁而发生物理膨胀。随后，用稀酸（12% HCl）将氧化铁颗粒完全去除。该纯化工艺在去除所有铁催化剂颗粒方面似乎非常有效。电子显微镜图像和拉曼光谱数据表明，纯化过程不会破坏纳米管的石墨结构。
