用共振增强双光子电离法实时研究甲烷无氧芳构化反应的诱导期

随着天然气的开发与综合利用,甲烷的活化与转化过程引起人们越来越多的关注,甲烷在无氧条件下催化转化为芳烃已成为甲烷利用领域的热门课题1～4].人们已采用XRD,FT-IR,BET,NMR及XPS等多种方法研究甲烷无氧芳构化反应.在优化反应条件和筛选催化剂的同时,对Mo/HZSM-5催化剂的双功能催化本质也有了相当深入的认识.研究表明,甲烷无氧芳构化反应存在诱导期,在诱导期内,催化剂表面可发生物理和化学变化,并逐渐形成催化活性位.各反应产物在诱导期内的变化是同反应机理密切相关的.

Real-Time Study of Induction Period of Methane Aromatization by Resonance-Enhanced Two-Photon Ionization

The induction period of dehydrogenation and aromatization of methane over Mo/HZSM 5 was studied by real time resonance enhanced two photon ionization (RE2PI) technique. It is found that the formation of benzene evidently involves three different stages during the induction period. This probably means that the active sites of the catalysts undergo a transformation from Mo 6+ species to lower valence Mo species, and the Mo 6+ species also has feeble catalytic activity.