Selective catalytic oxidation of ammonia into nitrogen over PCH modified with copper and iron species

Porous clay heterostructures (PCH) obtained on the basis of the synthetic saponite was used as a catalytic support for the deposition of transition metal (Cu, Fe) oxides. Transition metal oxides were introduced into the parent as well as ammonia treated PCH support by the ion-exchange method. The obtained catalysts were characterized with respect to their textural parameters (BET), composition (EPMA), chemical nature of the introduced transition metal species (UV-vis-DRS) and surface acidity (NH3-TPD, FTIR). The modified PCH materials were tested as catalysts for the selective oxidation of ammonia to nitrogen and water. The studied catalysts have shown a very high selectivity towards N-2, which did not drop below 90% in a large studied temperature range (150-550 degrees C). However, the Cu-containing samples were active at temperatures significantly lower than PCH modified with iron. (c) 2006 Elsevier B.V. All rights reserved.