Catalytic Performance of One-Pot Synthesized Fe-MWW Layered Zeolites (MCM-22, MCM-36, and ITQ-2) in Selective Catalytic Reduction of Nitrogen Oxides with Ammonia

The application of layered zeolites of MWW topology in environmental catalysis has attracted growing attention in recent years; however, only a few studies have explored their performance in selective catalytic reduction with ammonia (NH3-SCR). Thus, our work describes, for the first time, the one-pot synthesis of Fe-modified NH3-SCR catalysts supported on MCM-22, MCM-36, and ITQ-2. The calculated chemical composition of the materials was Si/Al of 30 and 5 wt.% of Fe. The reported results indicated a correlation between the arrangement of MWW layers and the form of iron in the zeolitic structure. We have observed that one-pot synthesis resulted in high dispersion of Fe3+ sites, which significantly enhanced low-temperature activity and prevented N2O generation during the reaction. All of the investigated samples exhibited almost 100% NO conversion at 250 degrees C. The most satisfactory activity was exhibited by Fe-modified MCM-36, since 50% of NO reduction was obtained at 150 degrees C for this catalyst. This effect can be explained by the abundance of isolated Fe3+ species, which are active in low-temperature NH3-SCR. Additionally, SiO2 pillars present in MCM-36 provided an additional surface for the deposition of the active phase.

Automated summary

The application of layered zeolites of MWW topology in environmental catalysis, especially in selective catalytic reduction with ammonia (NH3-SCR), has been receiving increasing attention. In this study, Fe-modified NH3-SCR catalysts supported on MCM-22, MCM-36, and ITQ-2 were synthesized via a one-pot method for the first time. The results showed a correlation between the arrangement of MWW layers and the form of iron in the zeolitic structure. The one-pot synthesis resulted in high dispersion of Fe3+ sites, leading to enhanced low-temperature activity and prevention of N2O generation. Fe-modified MCM-36 exhibited the most satisfactory activity with 50% NO reduction at 150 degrees C.