| Abstract
| - IM5 is a recently discovered zeolite that presents a high hydrothermal stability and, whenexchanged with cobalt, shows a high activity for the selective catalytic reduction of NO withpropane. The catalytic behavior of a cobalt-exchanged IM5 zeolite is compared with that of acobalt-exchanged ZSM5 zeolite. The state of the cobalt in the zeolite and the influence of thepartial pressure of oxygen, reaction temperature, and the presence of water and SO2 are studied.It is shown that cobalt is mainly as Co2+ in a tetrahedral environment, although the presenceof a small amount of other cobalt states cannot be rejected. The material is very active for theselective catalytic reduction of NOx with propane at 723 K and, what is important, with a highoxygen concentration. The presence of possible catalyst poisons such as SO2 and water does notresult in a deactivation of the Co−IM5.
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