Theoretical analysis of N₂O to N₂ conversion during the catalytic decomposition of NO by Cu-zeolites

Catalytic reactions of N₂O in Cu-exchanged silica zeolites (ZSM-5) have been investigated theoretically using first-principles density functional theory (DFT). We consider four possible reaction paths for the production of N₂, including (i) ZCu + N₂O → ZCuO + N₂, (ii) ZCuO + N₂O → ZCuO₂ + N₂, (iii) ZCu + NO + N₂O → ZCuNO₂ + N₂ and (iv) ZCu + NO₂ + N₂O → ZCuNO₃ + N₂ ("Z" refers to zeolites). Reactions (i) and (iii) are found to be the most favorable, whereas reactions (ii) and (iv) have much larger barriers. The implication for N₂O reactions in non-selective reduction of NO by CO is also discussed.