Effect of Pretreatments in Various Atmospheres on the Transient DeNO x Activity of a Cu-MFI Catalyst

Author： Gaudin C. Duprez D. Mabilon G. Prigent M.

ISSN： 0021-9517

Source： Journal of Catalysis, Vol.160, Iss.1, 1996-01, pp. : 10-18

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Steady-state and transient activities of a 1.47 wt% Cu-MFI (Si/Al = 27) catalyst in the selective catalytic reduction of NO x with hydrocarbons (HC) were investigated in the 473-723 K temperature range with propene and propane as reducers. Under steady-state conditions (1000 ppm NO + 1700 ppm HC + 5% O 2 ), propene gives the highest NO conversion at 673 K while propane is a reducer which is much better at 573-623 K. Transient activities were also investigated by comparing the NO conversion in the presence of O 2 after different pretreatments in HC or HC + NO. On the fresh, non-pretreated catalyst, a NO uptake can be observed without any formation of N 2 . Reacting the pretreated catalyst with NO + O 2 leads to transient formation of N 2 and CO 2 with the following efficiency of the hydrocarbons: propene > propane. The pretreatment in HC + NO is significantly better than in HC alone and leads to formation of nitrogen-containing species which are further decomposed into N 2 and CO 2 , but only in the presence of O 2 . These nitrogen-containing species cannot react with NO alone.