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Temperature programmed desorption/surface-reaction study of an anodic alumina supported Ag catalyst for selective catalytic reduction of nitric oxide with propene

Paper ID Volume ID Publish Year Pages File Format Full-Text
48300 46500 2008 12 PDF Available
Title
Temperature programmed desorption/surface-reaction study of an anodic alumina supported Ag catalyst for selective catalytic reduction of nitric oxide with propene
Abstract

On an anodic alumina supported silver catalyst with a low Ag loading (1.68 wt.%), NOx (NO/He, NO/O2/He, NO2/He) adsorption measurements and NOx-temperature programmed decomposition (TPD)/temperature programmed surface-reaction (TPSR) measurements in different gas streams (He, C3H6/He, C3H6/O2/He) were conducted to investigate the formation, consumption and reactivity of surface adsorbed NOx species.During NO adsorption, no noticeable uptake of NO was detected. Introducing oxygen greatly improved the formation of ads-NOx species. A greater quantity of surface nitrate species was found after NO2 adsorption, accompanied with gaseous NO release. The result of TPSR demonstrates the surface nitrate species can be effectively and preferentially reduced by propene. When introducing oxygen into the propene gas stream of TPSR test, the significantly increased amount of reacted nitrate undoubtedly shows the importance of oxygen in activating propene. The pathway for the selective reduction of NOx in the presence of excess oxygen is proposed to pass through the selective reduction of the adsorbed nitrate species with the activated propene.The enhanced NOx conversion when replacing NO with NO2 was attributed to the stronger NOx adsorption capacity and oxidation ability of NO2, than those for NO. With increasing oxygen concentration, the difference between NO and NO2 would gradually decrease, and finally disappear in a high excess of oxygen.

Keywords
Ag; Anodic alumina; TPD/TPSR; Selective catalytic reduction; De-NO
First Page Preview
Temperature programmed desorption/surface-reaction study of an anodic alumina supported Ag catalyst for selective catalytic reduction of nitric oxide with propene
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 79, Issue 4, 8 March 2008, Pages 382–393
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis