The Quantum Chemistry Study Of NO_x Adsorption And Catalitic Decomposition On The ZSM-5Zeolite

In the study, the optimized geometry, adsorption energy（ΔEads）, Mulliken population,Infrared （IR） of NO and N₂O adsorption over the H-ZSM-5, Cu-ZSM-5and Fe-ZSM-5zeoliteswere calculated by the density functional theory （DFT） method at the level of B3LYP/6-31G（d,p）.On the basis of experimental results, NO and N₂O adsorption on the different acid sites ofH-ZSM-5zeolites, and NO and N₂O adsorption on the Cu ion and Fe ion of ZSM-5zeolites wereresearched separately. The results show.（1） The clusters model, basis set, zero-point correction, adsorption temperature and pressureimpact on the calculation precision by the single fact method. The computation basedwere identified；（2） NO and N₂O adsorption on H-ZSM-5zeolite were physical adsorption. And NO and N₂Oadsorption on Fe-ZSM-5and Cu-ZSM-5zeolites were chemical adsorptionn. All of theadsorption were exothermic process；（3） the adsorption ability of NO and N₂O adsorption on the acid sites of the H-ZSM-5zeolites were not different. The adsorption ability of α acid sites were the strongest;（4） the adsorption ability of NO and N₂O adsorption on the Cu ion and Fe ion of the acid sitesin ZSM-5zeolites were not different, the adsorption ability of the α acid sites of Cu ionand Fe ion were the strongest.On the base of the theory calculation, based on IRC theory, Mulliken population analysis, the study verify that N2O adsorption on Fe ion of the acid sites in Fe-ZSM-5zeolitesinduced the breakage of N-O bond, N2desorption, and then another N2O adsorption on Fe ion, thebreakage of N-O bond, the left two O stom to form molecules of oxygen gas was through threeparts and nine steps to complete the entire catalytic circulation by Charge Transfer（CT）, thestructure of zeolites、α-O and Fe played an important role in the catalytic degradation reaction.