单壁碳纳米管储氢研究  

The mechanism of hydrogen storage in single-walled carbon nanotube

作　　者：阎世英[1] 杨自钦[2] 

机构地区：[1]青岛大学物理科学学院,青岛266071 [2]北京大学物理学院,北京100871

出　　处：《原子与分子物理学报》2012年第6期941-947,共7页Journal of Atomic and Molecular Physics

基　　金：山东省高等学校科技计划项目(J10LA02)

摘　　要：利用Gaussian03程序计算出C-H键的键能是1.88 eV,键长是0.113 nm.已知H-H键能是4.748 eV,键长是0.074 nm.显然,H-H键能大于C-H键的键能,所以在常温常压下碳纳米管储氢时,以物理吸附H_2分子为主,化学形式的C-H键吸附为辅.另外,利用LJ势能函数,计算了H_2分子在碳纳米管中C原子所成的六边形中心正上方、C原子正上方以及相邻两C原子中间正上方时H_2分子与碳纳米管之间的势能.得到无论H_2分子是被吸附到管内或管外,还是被吸附到中间区域或两端区域,都是H_2分子在C原子所成的六边形中心正上方时能量最低.当H_2分子被吸附到碳纳米管中间区域时,管内和管外的H_2分子距管壁的距离分别是0.320 nm和0.309 nm;而当H_2分子被吸附到碳纳米管两端区域时,这两个距离分别是0.324 nm和0.313 nm.The C--H bong energy, 1.88 eV, and the bond length, 0. 113 nm, are obtained from the calculation with Gaussian03 program. It is known that the H--H bong energy is 4. 748 eV and the bond length is 0. 074 nm. Obviously, H--H bond energy is greater than the C--H bond energy. So the hydrogen storage of carbon nanotube is due mainly to the physisorption and the chemisorption almost doesn＇t happen at moderate temperatures and pressures. In addition, LJ potential has been used to calculate the potential between a H2 molecule and the carbon nanotube. The H2 molecule is placed in three radial distributions： （a） above the center of a hexagon surrounded by 6 C atoms, （b）above the center of a C--C bond, （c）above the center of a C atom. The result shows that whether the H2 molecule is adsorbed into and outside the nanotube or to the center and the end of the nanotube, there is the lowest potential when the H2 molecule is above the center of a hexagon surrounded by 6 C atoms. When the H2 molecule is absorbed to the center of nanotube, the equilibrium distances between it and the nanotube wall for H2 adsorbed into and outside the nanotube are 0. 320 nm and 0. 309 nm, respectively. While in the case that it is adsorbed to the end of the nanotube, the two corresponding distances are 0. 324 nm and 0. 314 nm, respectively.

关 键 词：碳纳米管 储氢 LJ势 碳氢键能 

分 类 号：O642[理学—物理化学]