Ag^＋交换沸石分子筛吸附小分子的结构与电子性质的密度泛函理论研究

采用密度泛函理论研究了Ag^＋交换沸石分子筛及其吸附NO，H2O，CO，H2S和SO2的结构及电子性质，并对簇模型进行了自然键轨道（NBO）分析，用分子中的原子（AIM）理论研究了相关键的拓扑性质．研究结果表明，NO，CO和SO2的吸附导致了Ag^＋和沸石骨架上氧的距离缩短，这主要是因为NO，CO和SO2的吸引电子能力较大使Ag-O1和Ag-O2共价性增强所致；而H2O，H2S的吸附导致了Ag^＋和沸石骨架上氧的距离增大，可归因于H2O，H2S的吸引电子能力弱使Ag-O1和Ag-O2共价性减小所致．

Density Functional Theory Study on Structural and Electronic Properties of Ag^＋ Exchanged Zeolites and Its Adsorbing Small Molecules

Calculations were performed on Ag^＋ exchanged zeolite and its adsorbing NO, H2O, CO, H2S, SO2 by means of density functional theory. The structural and electronic properties were highlighted. The electronic properties of NBO were carried out and the topological properties were completed by atom in molecules（AIM） analyses. The calculation results suggest that the adsorption of NO, CO, and SO2 on Ag^＋ exchanged zeolites can give rise to the contraction of distances between Ag ＋ and two oxygen atoms from zeolite framework, which is assigned to the enhancement of covalent character of Ag-O1 and Agpower of NO, CO and SO2. However, the adsorption of H2O and H2 bonds due to the high electron attracting S on Ag^＋ exchanged zeolites can induce the protraction of distances between Ag^＋ and two oxygen atoms from zeolite framework, which is ascribed to the decrease of covalent character of Ag-O1 and Ag-O2 bonds because of the low electron attracting power of H2O and H2S.