用微米级LaNi_5为催化剂生长的碳管的ESR谱研究  

An Electron Spin Resonance Study of Carbon Nanotubes Synthesized Using LaNi_5 Alloy Micro-Particles as Catalyst

作　　者：张海燕[1] 陈易明[1] 曾国勋[1] 陈进[1] 曹晓国[1] 

机构地区：[1]广东工业大学材料与能源学院,广东广州510006

出　　处：《波谱学杂志》2007年第1期63-70,共8页Chinese Journal of Magnetic Resonance

基　　金：国家自然科学基金资助项目(20271014;50372013);广东省自然科学基金资助项目(036918)

摘　　要：用微米级LaNi5合金粉末为催化剂，以乙炔为原料，采用化学气相沉积（CVD）法合成了多壁碳纳米管．在100-290K温度下测量了41um≤d≤150um粒径催化剂制备的不同直径分布的碳纳米管的电子自旋共振（ESR）谱，研究了测量温度、微米级催化剂粒径及制备过程的氢气氛对生成的碳纳米管的ESR谱线型、g因子、线宽的影响．发现碳纳米管的g因子随其直径的增大而增大，分别为2．0400（催化剂粒径41um≤d≤50um，碳纳米管的直径分布为10nm到20nm）和2．0898（催化剂粒径100um≤d≤150um，碳纳米管的直径分布为70nm到120nm）。发现小管径纳米管的ESR谱图有一个峰，而大管径纳米管的ESR谱图有两个峰A和B，且随测量温度的升高，峰B强度增大．Multi-wall carbon nanotubes were synthesized from C2 H2 by chemical vapor deposition （CVD） method using LaNi5 alloy micro-particles with diameters ranging from 41 to 150 um as catalyst. Electron spin resonance （ESR） spectra of purified carbon nanotubes were acquired at different temperatures between 100 and 290 K. The effects of the size of the catalyst particles used and addition of hydrogen gas during synthesis on the ESR characteristics （i. e. , line shape, g-value and linewidth） of the produced nanotubes were investigated. It was found that the g-values of the produced nanotubes increase with their diameters, nanotubes having diameters between 10 and 20 nm （synthesized with catalyst particles having diameters between 41 to 50 um） have an averaged g of 2. 0400, while those having diameters between 70 and 120 nm （synthesized with catalyst particles having diameters between 100 to 150 um） have an averaged g of 2.0898. It was also found that there is only one peak in the ESR spectra of carbon nanotubes with small diameters, while the nanotubes having larger diameters show two peaks, and the intensity of the additional peak increases with temperature.

关 键 词：电子自旋共振 碳纳米管 化学气相沉积 LaNi5合金微米粒子 

分 类 号：O482.53[理学—固体物理]