Nitrous oxide pollution abatement is an important environmental problem due to the high greenhouse potential of N2O and its ozone-depleting properties. One of the available options is the direct catalytic N2O decomposition. Kapteijn et al. [1] presented an excellent review on catalytic N2O decomposition. According to it, active catalysts often contain copper, cobalt, iron, or noble metals such as palladium, rhodium, ruthenium, etc. Different catalysts show different sensitivity to other gases such as water, NOx, oxygen. For example, copper catalysts are strongly inhibited by oxygen but the iron-containing ones are not. NO poisons most catalysts, however it promotes the reaction catalysed by Fe- ZSM-5 since it removes the adsorbed oxygen to form NO2. Generally all catalysts are poisoned by water to a different extent. Thus most catalysts active in the presence of water, NOx and oxygen were found to contain iron, cobalt, rhodium, and ruthenium.