摘要
使用量子化学计算方法,通过对密度泛函理论(DFT)的应用,采用周期性的分子模型(vaccumslab),模拟计算了甲烷和甲基在Ni(111)表面的吸附和解离(CH4(g)→CH3(ads)+Hads→CH2(ads)+2Hads)。甲烷、甲基和亚甲基分别吸附于Ni(111)表面的hcp、bridge和bridge位置。以物理吸附于催化剂表面的甲烷为反应物,化学吸附于催化剂表面的亚甲基和氢为产物,计算得到甲烷和甲基的解离能分别为42kJ/mol和45 5kJ/mol,活化能分别为202 2kJ/mol和98 2kJ/mol,并对解离路径进行了详细的分析。
The adsorption and dissociation of methane and methyl on Ni(1 1 1)surface have been investigated(CH_(4(g))→CH_(3(ads))+H_(ads)→CH_(2(ads))+2H_(ads))with quantum chemistry calculations using DFT method and periodic molecular model. Methane adsorbed weakly at hexagonal-close-packed (hcp) hollow site, methyl adsorbed strongly at bridge site, and methylene also at bridge site. In the reaction, methane physically adsorbed on surface act as reactant, and methylene and hydrogen coadsorbed on surface as product. The calculated dissociation energies and barriers are 42 kJ/mol and 202.2 kJ/mol for methane decomposition and 45.5kJ/mol and 98.2 kJ/mol for methyl decomposition, respectively. The framework of the transition states and path coordinate are analyzed in detail.
出处
《天然气化工—C1化学与化工》
CAS
CSCD
北大核心
2004年第3期13-18,共6页
Natural Gas Chemical Industry
关键词
量子化学
DFT
甲烷
解离
quantum chemistry
DFT
methane
dissociation
