Selective catalytic reduction of NOx with NH3 over H-ZSM-5: Influence of transient ammonia supply
Journal article, 2003

The effect of ammonia supply on the selective catalytic reduction of NOX over zeolite H-ZSM-5 was investigated using step response experiments between 200 and 500 degrees C. For inlet NO:NO2 ratios > 1, the activity for NOX reduction transiently increased when NH3 was removed from the feed. For NO:NO2 ratios less than or equal to 1, the NOX reduction however decreased. By pulsing NH3 to the feed, the activity for NO reduction was enhanced up to five times compared to continuous supply of ammonia. For NO:NO2 ratios exceeding one, also the selectivity towards N2O formation was lower with transient ammonia supply. Temperature programmed reaction experiments with preadsorbed NH3 showed highest initial NOX reduction activity when ammonia had been adsorbed at 300 or 250 degrees C compared to 200 degrees C. A minimum in NO reduction was observed at 130 degrees C independent of the ammonia adsorption temperature. For NO:NO2 ratios > 1, the results strongly indicate that NO oxidation is the rate determining step in the ammonia selective catalytic reduction (NH3-SCR) reaction over H-ZSM-5.

H-ZSM-5

NOx reduction

selective catalytic reduction

lean deNOx

ammonia transients

Author

Mikaela Wallin

Chalmers, Department of Materials and Surface Chemistry, Applied Surface Chemistry

Competence Centre for Catalysis (KCK)

Carl-Johan Karlsson

Chalmers, Department of Materials and Surface Chemistry, Applied Surface Chemistry

Competence Centre for Catalysis (KCK)

Magnus Skoglundh

Competence Centre for Catalysis (KCK)

Chalmers, Department of Materials and Surface Chemistry, Applied Surface Chemistry

Anders Palmqvist

Chalmers, Department of Materials and Surface Chemistry, Applied Surface Chemistry

Competence Centre for Catalysis (KCK)

Journal of Catalysis

0021-9517 (ISSN) 1090-2694 (eISSN)

Vol. 218 2 354-364

Driving Forces

Sustainable development

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

Transport

Energy

Materials Science

Subject Categories

Physical Chemistry

Chemical Engineering

Chemical Sciences

DOI

10.1016/S0021-9517(03)00148-9

More information

Created

10/7/2017