Hoạt tính xúc tác của Cu trong phản ứng phân hủy N2O

Abstract

The focus of the performed studies is Cu containing catalysts for nitrous oxide decomposition in the temperature range of 200÷600 ^oC. Catalytic samples have been synthesized by wet impregnation method. Prepared materials are characterized by means of XRD and N₂ adsorption/desorption. The obtained results reveal that Cu or Fe supported catalysts, especially Cu (or Fe)/ZSM-5, exhibit very promising activity and they are good catalysts for decomposition of N₂O. An optimal copper loading of 5 wt% is found. Further increase of Cu-loading to 7 % results in the formation of segregate and less active phase. Of the three supports, ZnO, Al₂O₃ and ZSM-5 used, H-ZSM-5 produces the most effective catalyst for N₂O decomposition due to acid nature, high surface area and high order pore structure. The decomposition of N₂O follows two stages. At low temperatures, N₂O decomposes to N₂ and surface oxygen atoms. The second high temperature stage involves the formation of O₂ and the rate of oxygen formation correlates with catalytic activity. Fast desorption of O₂ increases the number of effective sites and therefore the catalyst is regenerated.

Keywords. Decomposition, N₂O, copper, ZSM-5, Al₂O₃