Density Functional Theory Study of Ethylene Protonation over HZSM-5 Zeolite with Neighboring Bronsted Acid Sites

作者：Ren Jue; Zhou Danhong^*; Li Jinghong; Cao Liang; Xing Shuangying

来源：Chinese Journal of Catalysis, 2011, 32(6): 1056-1062.

DOI：10.3724/SP.J.1088.2011.10110

• HZSM-5 zeolite
• ethylene protonation
• Bronsted acid site
• neighboring acid sites
• density functional theory

By the density functional theory method, the effect of different acid sites and neighboring acid sites on ethylene protonation over HZSM-5 zeolite was investigated. The calculations were based on the 20T cluster model and carried out at the B3LYP/6-31G(d,p) theoretical level. The structure, atomic charges, and the energy of the ethylene adsorption species, transition state, and the surface alkoxide products were examined. The results indicated that the next-nearest-neighboring acid sites led to obvious decrease in acid strength and adsorption energy but slight decrease in activation energy, while the next-next-nearest-neighboring acid sites had a very slender effect on acid strength and the affection on ethylene protonation could be neglected. The activation energy and reaction energy had no inevitable correlation with the acid strength but virtually depended on the location and chemical environment of the acid sites in HZSM-5 zeolite. If the transition-state structure is much resembling to the carbenium ion, the activation energy would be higher.

• 出版日期2011-6
• 单位辽宁师范大学