Adsorption of NO and N_2O on Fe-BEA and H-BEA zeolites

摘要

FT-IR (Fourier-transform infrared) spectroscopy and density function theory (DFT) methods have been applied to the investigation of the interaction of NO and N_2O with Fe~(3+) species in a beta zeolite (BEA). The geometries for H-BEA and Fe-BEA represented as 10T cluster, and NO and N_2O adsorption on them in η~1-O and η~1-N modes have been completely optimized. The results show that NOx could be adsorbed on Fe~(3+) species and Bronsted acid sites in two modes, but NOx is mainly bonded by N to H or Fe atom and the iron site is preferred. NOx adsorbed on Fe~(3+) species is more stable than on Bransted acid sites. Adsorption energies for N_2O and NO follow the order of NO > N_2O, predicating that the affinity of NO molecule on BEA zeolite is much stronger than N_2O molecule on BEA zeolite.