Fe-Exchanged Zeolites for Selective Catalytic Reduction of Nitric Oxide with Ammonia

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

The objective of this proposal is to explore the effectiveness of iron-exchanged zeolites as catalysts for the selective catalytic reduction (SCR) of nitrogen oxide (Nox) species. In preliminary work the PI has found that several zeolites including ZSM-5 are much more active than the commercial vanadia catalysts currently used in many stationary SCR systems. Also, these new catalysts are more resistant to deactivation by sulfur oxides and water. A series of iron-exchanged zeolites will be prepared using four different methods: conventional solution ion-exchange, improved aqueous ion-exchange, chemical vapor deposition, and solid-sate ion exchange. Zeolites with small pores and low Si/Al ratios were found to be most effective and will be used in this project. Rare earth cations and oxides will be studies as promoters. Catalysts will be characterized by neutron activation analysis and other surface analysis techniques. Steady-state kinetics and the mechanism for NO reduction will be studies in parallel with ammonia oxidation. Nitrogen oxides resulting from combustion remain a major source of air pollution. This study will provide a fundamental understanding of the catalytic reaction mechanism for NO reduction by ammonia on Fe-zeolites, leading to the development of superior SCR catalysts.