ISSN:
1572-879X
Keywords:
lean burn
;
NOx storage release catalyst
;
CO2 effect
;
barium trap
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A barium‐containing three‐way automotive emission catalyst was submitted to a NOx storage step in flowing lean gas mixture containing 340 ppm NO and 8 vol% O2 in helium. NOx release was carried out in the 250–550°C temperature range, either in pure helium or in the presence of a 10 vol% CO2 in helium mixture. It was shown that at 450–550°C all of the stored NOx on the barium trap can be released fastly in the CO2‐containing gas mixture or, after a longer time, in pure helium: these data show that NOx release can occur in the absence of a reducing agent. The NOx release was not complete at 350°C and did not occur at 250°C. The assisting effect of CO2 as regards to NOx release was interpreted in terms of the existence of the CO2,gas + *NO2,stored ⇌ *CO2,stored + NO2,gas equilibrium, suggesting the competitive storage of CO2 and NO2 for a unique type of barium storage sites (*).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1019034402660
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