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Indexed by:期刊论文

Date of Publication:2016-07-01

Journal:10th International Congress on Catalysis and Automotive Pollution Control (CAPoC)

Included Journals:SCIE、EI、CPCI-S

Volume:59

Issue:10-12

Page Number:952-960

ISSN No.:1022-5528

Key Words:Nitrogen oxides (NOx); Platinum catalyst; Ammonia; Nitrous oxide; Detailed mechanism

Abstract:The combination of NOx storage and reduction and in situ NH3 selective catalytic reduction (NSR-SCR) provides the benefits of simple structure, no external source of NH3, low precious metal consumption and high NOx reduction efficiency. The by-product ammonia is of importance in the NSR-SCR coupling system. Considering the formation of ammonia and another important side product N2O during the regeneration period of NSR, detailed mechanisms of H-2-NO and CO-NO reactions over Pt were developed. The mechanisms of H-2-NO and CO-NO reaction systems, which share the same NOx chemistries, are capable of reproducing experimental results from literature. Ammonia was shown highly sensitive to H-2/NO feed ratio. NH3 was formed at low temperatures and decomposed with increase of temperature. For different feed conditions, NHx related reactions showed similar influential tendency on NH3 generation, while the hydrogenation of NH showed much greater influence than the other two reactions. In CO-NO reaction system, the intermediate species N2O formed at low temperatures and reached a maximum production at about 320 degrees C. N2O decomposed into target product N-2 when temperature was further increased. The results of coverage and sensitivity analysis indicated that adsorbed CO(s) occupied most catalytic active sites over the whole temperature range of 100-500 degrees C investigated and showed strong adsorption energy, hindering NO adsorption process and NO(s) dissociation. As a result, the inadequacy of N-(s) species reduced the production of N-2 and N2O.