Experimental and density functional theory study of the adsorption of N₂O on ion-exchanged ZSM-5: Part II. The adsorption of N₂O on main-group ion-exchanged ZSM-5

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• 作者：Bo Zhang^a ; ^{bozhang@rcees.ac.cn} ; Yongan Lu^b ; Hong He^a ; ^{honghe@rcees.ac.cn} ; Jianguo Wang^b ; ^{jgw@zjut.edu.cn} ; Changbin Zhang^a ; Yunbo Yu^a ; Li Xue^a
• 关键词：N₂O adsorption ; ZSM-5 ; DFT ; ion-exchanged zeolites
• 刊名：Journal of Environmental Sciences
• 出版年：2011
• 出版时间：April 2011
• 年：2011
• 卷：23
• 期：4
• 页码：681-686
• 全文大小：223 K

文摘

The adsorption and desorption of N₂O on main-group ion-exchanged ZSM-5 was studied using temperature-programmed desorption (TPD) and density functional theory (DFT) calculations. TPD experiments were carried out to determine the desorbed temperature T_max corresponding to the maximum mass intensity of N₂O desorption peak and adsorption capacity of N₂O on metal-ion-exchanged ZSM-5s. The results indicated that T_max followed a sequence of Ba²⁺ > Ca²⁺ > Cs⁺ > K⁺ > Na⁺ > Mg²⁺and the amount of adsorbed N₂O on main-group metal cation followed a sequence of Ba²⁺ > Mg²⁺ > Ca²⁺ > Na⁺ > K⁺ > Cs⁺. The DFT calculations were performed to obtain the adsorption energy (E_ads), which represents the strength of the interaction between metal cations and the N-end or O-end of N₂O. The calculation results showed that the N-end of the N₂O molecule was favorably adsorbed on ion-exchanged ZSM-5, except for Cs-ZSM-5. For alkali metal cations, the E_ads of N₂O on cations followed the order which was the same to that of T_max: Cs⁺ > K⁺ > Na⁺. The calculated and experimental results consistently showed that the adsorption performances of alkaline-earth metal cations were better than those of alkali metal cations.