多壁碳纳米管的制备及改性处理

用自制的镍 硅二元气凝胶作催化剂,合成了多壁碳纳米管.甲烷在680℃催化裂解120min,再升温至800℃继续裂解20min,得到多壁碳纳米管.TEM、HRTEM和Raman光谱分析表明,所得多壁碳纳米管与高定向石墨具有相似的层状结构,其管径分布均匀,约15～30nm左右,长径比大,管端封闭,并含有金属催化剂粒子;采用不同方法改性处理,发现经过稀硝酸浸泡和空气氧化处理后,能去除碳管中金属催化剂,同时碳纳米管管长变短,端帽开口,能有效利用内表面,比表面积增大.

Preparation and Modification of Multi-walled Carbon Nanotubes

Nickel-silica binary aerogels were prepared as the catalyst for the synthesis of multi-walled carbon nanotubes. The specific surface area of binary aerogels could be up to 1 342 m~2/g. Multi-walled carbon nanotubes were synthesized by the catalytic decomposition of methane at 680 ℃ for 120 min and then up to 800 ℃ for 20 min. The morphology and structure of multi-walled carbon nanotubes were investigated by TEM, HRTEM and Raman spectroscopy. The resuts revealed that the multi-walled carbon nanotubes with diameter 15～30 nm were of high quality, with uniform diameter and high length/diameter ratio, and the wall structure was similar with that of the highly oriented pyrolytic graphite (HPOG), but the cap of the tip were closed with some metal catalyst particles. The carbon nanotubes were modified with different methods. The results showed that when the carbon nanotubes were modified by soaking with dilute nitric acid and heated at high temperature in air,the metal catalyst particles disappeared, the length became short, the cap of the tip was destroyed, and the specific surface area was highly increased.