Catalytic Oxidation Reaction Mechanism of NO on Fe Modified ZSM-5 Zeolite by in Situ DRIFTS Experiment and DFT Study

The reaction mechanism of NO and O-2 on Fe modified ZSM-5 zeolite was studied in detail by in situ diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) respectively. According to the results of DFT, firstly NO molecule is adsorbed on the Fe-ZSM-5 zeolite activate site iron ion in eta-N adsorption mode, secondly O-2 is adsorbed on Z-Fe-NO to form Z-Fe-ONOO*, then via a transition state TS1 generates an adsorption state intermediate product NO3- which continuely reacts with the second NO molecule via a transition state TS2 to generate two NO2 molecules which subsequently desorb from Fe-ZSM-5 zeolite. The results of the quantitative calculation were in good agreement with that of in situ DRIFTS and this would provide important theoretical basis for the exploration of NO catalytic oxidation catalyst at low temperature.