The adsorption of NO2 and the NO + O2 reaction on Na-Y,FAU: an in situ FTIR investigation

Abstract

The adsorption of NO and NO₂ and the reaction between NO and O₂were investigated on a Na-Y,FAU zeolite. The interaction between NO and Na-Y is weak and no IR absorption feature is seen upon room temperature adsorption. On the other hand, several NO_x species were identified in the adsorption of NO₂ bonded to Lewis acidic (NO₃⁻, NO₂⁻) and basic sites (NO⁺ and [NO⁺][NO₂] and [NO⁺][N₂O₄]). In the NO + O₂ reaction, N₂O₃ was formed and adsorbed N₂O₃ was observed in addition to the species detected upon NO₂ adsorption. A series of experiments were conducted to unambiguously assign the IR features in the 2000–2120 cm⁻¹ spectral range. Through reaction and isotopic substitution (¹⁵NO and ¹⁸O₂) experiments, these bands were assigned to NO⁺ adsorbed onto framework O⁻ sites as charge compensating cations.