甲烷在Ni表面及La薄膜上激活解离化学吸附  

ACTIVATED CHEMISORPTION OF CH_4 ON Ni SURFACE AND La FILM

作　　者：邵淑敏[1] 席光康[1] 王君容[1] 李胜林[1] 杨学柱[1] 王金合 周志强[1] 贺添喜 于宝霞 

机构地区：[1]南开大学电子科学系,天津300071

出　　处：《物理化学学报》1992年第6期767-771,共5页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金

摘　　要：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 effect of translational kinetic energy E_k on the activated chemisorption ofCH_4 on Ni (polycrystal) surface and La film has been investigated using supersonicmolecular beam technique. No dissociative adsorption was observed for CH_4/Ni systemwhen E_k≤58. 5 kJ·mol^(-1) and for CH_4/La system when E_k≤52. 3 kJ·mol^(-1). Abovethese threshold values, the initial sticking probability s_0 increases linearly from 0 to0.54 for CH_4/Ni system as E_k increases from 58. 5 to 63.8 kJ·mol^(-1) and from 0 to0.49 for CH_4/La system as E_k increases from 52. 3 to 63. 8 kJ·mol^(-1). These resultsindicate that a rather direct chemisorption process, rather than a classical precursormechanism proceeds in these systems. Finally the apparent activation energies obtainedare 46.8 kJ·mol^(-1) and 38. 1 kJ·mol^(-1) for CH_4/Ni and CH_4/La systems respectively.

关 键 词：甲烷 镍 镧 激活 化学吸附 

分 类 号：O623.11[理学—有机化学]