论文部分内容阅读
利用分子束技术改变甲烷的平动能E_k来研究E_k及其法向分量E_n对甲烷在Ni表面及La薄膜上激活解离吸附的影响。对CH_4/Ni及CH_4/La系统,当甲烷的平动能E_k分别低于58.5kJ·mol~(-1)及52.3kJ·mol~(-1)时,没观察到甲烷的解离吸附。当甲烷的平动能超过此阈值时,即对CH_4/Ni系统,当Ek=58.5增至63.8kJ·mol~(-1)时,初始沾着几率s_0由0至0.54线性增加;对CH_4/La系统,当E_k=52.3增至63.8kJ·mol~(-1)时,S_0由0至0.49线性增加。这些结果表明,两个系统的化学吸附是不经过前趋态的直接化学吸附。最后求出CH_4/Ni,CH_4/La系统的表观活化能分别为46.8kJ·mol~(-1)和38.1kJ·mol~(-1)。
The effects of E_k and its normal component E_n on the activation and deactivation of methane on Ni surface and La thin film were investigated by using molecular beam technique to change the translational kinetic energy of methane, E_k. For CH_4 / Ni and CH_4 / La systems, no methane dissociative adsorption was observed when the translational kinetic energy E_k of methane was below 58.5kJ · mol -1 and 52.3kJ · mol -1, respectively. When methane translational kinetic energy is above this threshold value, that is, when Ek = 58.5 increases to 63.8 kJ · mol -1 for CH_4 / Ni system, the initial stained probability s_0 increases linearly from 0 to 0.54. For CH_4 / La System, when E_k = 52.3 increases to 63.8kJ · mol ~ (-1), S_0 increases linearly from 0 to 0.49. These results show that the chemisorptions of both systems are direct chemisorption without prior state. Finally, the apparent activation energies of CH_4 / Ni and CH_4 / La systems were found to be 46.8 kJ · mol -1 and 38.1 kJ · mol -1, respectively.