Selective catalytic reduction of NO with ammonia over porous clay heterostructures modified with copper and iron species

Porous clay heterostructures (PCH), obtained on the basis of synthetic saponite, were modified with copper and iron ions by an ion-exchange method and tested as catalysts for the selective reduction of NO with ammonia (NH₃-SCR). Transition metal ions were introduced into H⁺ and NH₄⁺ forms of PCH. The catalysts were characterized with respect to their texture (BET), composition (EPMA), coordination of transition metals (UV–vis-DRS) and surface acidity (FT-IR, NH₃-TPD). The PCH-based catalysts have been found to be active, selective and stable in the NH₃-SCR process. The Cu-containing catalysts effectively operated at temperatures significantly lower than the Fe-modified samples. The catalyst obtained by exchanging copper ions in the ammonium form of PCH was considerably more active compared to the sample obtained from H⁺-PCH.