N2O has recently been recognized as one kind of hazardous gas not only having a strong green effect but also depleting the ozone layer in the stratosphere. The direct decomposition of N2O using transition-metal-ion modified zeolite (TMI-Z) as the catalyst is believed to be a promising and economical method for N2O abatement. Zeolite catalyst consists of an infinite network of TO4 tetrahedra (T = Si, Al, etc.) having various physic-chemical properties, among which the electric field effect (EFE) constituting one of the most important properties plays a major role in the heterogeneous catalytic reactions. However, up to now, few works have been devoted to establishing the relationship between EFE and related catalytic behavior for the zeolite catalyst. In light of that, present work systematically investigated the local EFE of the TMI (Fe, Co, Cu)-BEA on N2O direct dissociation based on density functional theory (DFT) including mechanism simulation and charge transfer (CT) analysis, wherein the approaches of Mulliken CT analysis, frontier molecular orbital (FMO) and N2O-DRIFTS were employed. The results reveal that (I) for the O2 formation mechanism, the EFEs of TMI-BEA and formed aO greatly influenced adsorption and further activation of N2O through the CT, which was quantitatively determined by the FMO gaps between TMI-BEA and N2O; (II) for the NOx formation mechanism, the weak EFEs of Fe-BEA and formed aO during N2O adsorption through its N end gave a clue of low NO selectivity of Fe-BEA. Meanwhile, through the EFE study of present work, we also want to provide a new idea for the zeolitic heterogeneous reaction system based on the EFE point of view: the EFE study of TMI-Z can give a detailed investigation of the electronic properties of the TMI-Z, which facilitates the understanding of the reaction mechanism and also clarify the principle for catalyst design.

Mechanistic insight on electric filed effect of TMI (Fe, Co, Cu)-BEA during N<sub>2</sub>O direct dissociation based on DFT

248th National Meeting (2014)

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Mechanistic insight on electric filed effect of TMI (Fe, Co, Cu)-BEA during N2O direct dissociation based on DFT

Mechanistic insight on electric filed effect of TMI (Fe, Co, Cu)-BEA during N₂O direct dissociation based on DFT