Determining the characteristics of a Co-zeolite to be active for the selective catalytic reduction of NOx with hydrocarbons

Abstract

The aim of this work is to study the activity, for the selective catalytic reduction (SCR) of NOx with hydrocarbons, of different containing cobalt zeolites, with different typologies and compositions. It has been found that in order to obtain an active catalyst for this reaction is necessary that the zeolite presents an adequate topology: medium size pores, a Si/Al ratio of 8–30 and the absence of big cavities. The cobalt must be ion exchanged, because if the metal is in the zeolite framework the active sites are not accessible to the reactants. In addition for a commercial use of the catalyst, it has to be hydrothermically stable. New zeolite structures as ITQ27 and ITQ7 that present those characteristics have been ion exchanged with cobalt and they have been tested for the SCR of NOx with propane, showing its potential as active catalysts for this reaction.