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Investigation of the selective catalytic reduction of NO by NH3 on Fe-ZSM5 monolith catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
49100 46549 2006 9 PDF Available
Title
Investigation of the selective catalytic reduction of NO by NH3 on Fe-ZSM5 monolith catalysts
Abstract

Fe-ZSM5 coated on cordierite monolith was investigated in the selective catalytic reduction (SCR) of NO with ammonia over a broad temperature range, applying simulated diesel exhaust gas conditions. The catalyst exhibited over 80% NOx reduction (DeNOx) from 400 to 650 °C at very good selectivity. The dosage of variable amounts of ammonia in the catalytic tests revealed that the SCR reaction is inhibited by ammonia. At very high temperatures DeNOx is reduced due to the selective catalytic oxidation (SCO) of ammonia to nitrogen and the oxidation to NO. Water-free experiments resulted in generally higher DeNOx values, which are explained by the inhibiting effect of water on the NO oxidation capability of Fe-ZSM5. The catalyst was stable upon thermal ageing and only 5–15% loss in DeNOx activity was observed after hydrothermal treatment. This loss in DeNOx is in parallel with a loss of ammonia storage capacity of the aged catalyst. Characterization by NH3 TPD and MAS 27Al NMR spectroscopy revealed dealumination of the zeolite by hydrothermal ageing, which reduces the Brønsted acidity of the catalyst.

Keywords
Fe-ZSM5; NOx conversion; Monolith; Stability; Urea SCR; Ammonia storage
First Page Preview
Investigation of the selective catalytic reduction of NO by NH3 on Fe-ZSM5 monolith catalysts
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 66, Issues 3–4, 20 July 2006, Pages 208–216
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis