Detailed mechanism of NO reduction by CO over rhodium
during rich period of diesel LNT

doi:10.3969/j.issn.1674-8484.2012.01.008

Abstract

Abstract: The process of diesel exhaust NO reduction using CO as the reductant during the rich period of lean
NOx trap (LNT) was investigated considering an important byproduct N2O. Detailed mechanisms for CO-NO
and CO-N2O reactions over rhodium catalyst were proposed to numerically simulate experimental results, with
different feed gas ratios for the CO-N2O reaction. Good agreement was obtained for both of the two reactions.
The results show that N2O, as an important intermediate during NO reduction, undergoes further reactions with
CO under certain conditions. Most of the N2 is produced through the N2O route during NO reduction at 475-
620 K. The influence of the feed gas CO concentration on the isolated CO-N2O reaction was probed, and the
rate-limiting step was determined to be the decomposition of N2O according to the analysis of the elementary
reaction rate.

Key words: diesel engine, lean NOx trap (LNT), nitrous oxide (N2O), carbon monoxide (CO), rhodium catalyst, detailed mechanism

CLC Number:

U 461.91

SU Qingyun, WANG Sheng, LI Yanbin, SHUAI Shijin, WANG Jianxin. Detailed mechanism of NO reduction by CO over rhodium
during rich period of diesel LNT[J]. Journal Of Automotive Safety And Energy, 2012, 3(1): 51-57.

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