碳纳米管及其H_2吸附体系的Raman光谱

利用紫外Raman光谱技术 ,对分别以CO和CH4为碳源、由化学催化法制备的两种多壁碳纳米管以及它们的H2 吸附体系进行Raman光谱表征 ,观测到可分别归属于类石墨结构的基频模G (1 5 80cm- 1 )和D (1 41 6cm- 1 ,缺陷诱导 ) ,以及它们的二阶和三阶组合频 2D(2 83 2cm- 1 ) ,D +G (2 996cm- 1 ) ,2G (3 1 6 0cm- 1 )和 2D +G (441 2cm- 1 )的Raman峰 ;H2在这些多壁碳纳米管上吸附有两种形式 :非解离吸附分子氢H2 (a)和解离吸附生成含氢表面物种CHX(x =3 ,2 ,1 ) ,所观测在 2 85 0 ,2 96 7和 3 95 0cm- 1 处的Raman谱峰可分别归属于表面CH2 基的对称C -H伸缩模 ,CH3基的不对称C -H伸缩模 ,以及吸附态分子氢H2 (a)的H -H伸缩模

Raman Spectra of Carbon Nanotubes and Their H2- Adsorption Systems

With an UV-Vis Raman System, Raman spectra have been taken on two kinds of multi-walled carbon nanotubes (MWCNTs), prepared from catalytic decomposition of CO and CH 4 on a Ni-Mg-O catalyst, respectively, and their H 2-adsorption systems. The Raman peaks at 1580 and 1416 cm -1 observed on the MWCNTs could be ascribed to the fundamental frequencies of G and D (induced by defects) modes, and the peaks at 2832, 2996, 3160 and 4412 cm -1 may be assigned to the second-order (2D,D+G,2G) and triad (2D+G) combination frequencies of the D and G modes, respectively. The results also indicated that adsorption of H 2 on the MWCNTs occurred in two forms, non - dissociated and dissociated, and the observed Raman peaks at 2850, 2967 and 3950 cm -1 may be assigned to symmetric C-H stretch of CH 2, asymmetric C-H stretch of CH 3, and H-H stretch of adsorbed molecular hydrogen H 2(a), respectively.