SO2 promotes the rate of N2O removal over Fe-zeolites more efficiently than other reducing agents (NH3) and promoters (NO); the effect of SO2 as selective reductant is independent of the framework type and composition, preparation method, and iron content, suggesting that its occurrence is not determined by a highly specific iron speciation.
![SO2-promoted catalytic N2O removal over iron zeolites](https://www.iciq.org/wp-content/uploads/2014/03/SO2-promoted-catalytic_CC5351.gif)