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Study of the “Fast SCR”-like mechanism of H2-assisted SCR of NOx with ammonia over Ag/Al2O3

Paper ID Volume ID Publish Year Pages File Format Full-Text
46700 46445 2012 9 PDF Available
Title
Study of the “Fast SCR”-like mechanism of H2-assisted SCR of NOx with ammonia over Ag/Al2O3
Abstract

It is shown that Ag/Al2O3 is a unique catalytic system for H2-assisted selective catalytic reduction of NOx by NH3 (NH3-SCR) with both Ag and alumina being necessary components of the catalyst. The ability of Ag/Al2O3 and pure Al2O3 to catalyse SCR of mixtures of NO and NO2 by ammonia is demonstrated, the surface species occurring discussed, and a “Fast SCR”-like mechanism of the process is proposed. The possibility of catalyst surface blocking by adsorbed NOx and the influence of hydrogen on desorption of NOx were evaluated by FTIR and DFT calculations.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Presence of both Ag and Al2O3 is vital for high activity of Ag/Al2O3 in NOx SCR. ► The primary role of Ag is the H2-assisted oxidative activation of NO. ► The second role of hydrogen is the removal of nitrates blocking the Al2O3 surface. ► NO, NO2 and NH3 can react over pure alumina according to “Fast SCR” mechanism. ► The results are obtained using transient experiments, FTIR and DFT calculations.

Keywords
Ag/Al2O3; Alumina; NOx SCR; Fast SCR; FTIR
First Page Preview
Study of the “Fast SCR”-like mechanism of H2-assisted SCR of NOx with ammonia over Ag/Al2O3
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volumes 113–114, 22 February 2012, Pages 228–236
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis