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The alteration of the performance of field-aged Pd-based TWCs towards CO and C3H6 oxidation

Paper ID Volume ID Publish Year Pages File Format Full-Text
47520 46474 2009 12 PDF Available
Title
The alteration of the performance of field-aged Pd-based TWCs towards CO and C3H6 oxidation
Abstract

The deactivation of a three-way catalyst (TWC) included in warm-up catalytic converters (WCC) employed in passenger vehicles has been examined with respect to the catalyst field mileage by drivers. By a sweep test (ST) under the A/F oscillation of 1 Hz simulating the actual operation of a gasoline engine, the gradual deactivation of CO oxidation activity under rich condition over the Pd TWCs customer-aged was clearly observed with respect to the catalyst mileage, while the oxidation activity of C3H6 had been hardly altered. No proportional dependence of the deactivation of the CO and C3H6 oxidation activity on the catalyst mileage, however, was determined by both a steady-state sweep test (st-ST) and a light-off test (LOT) without A/F perturbation, although the initial deactivation of both reactions by both test modes was apparent. The sintering of noble metal (NM) itself might not be the only cause for the deactivation of TWC with respect to the catalyst aging mileage. The gradual alteration of the oxygen storage capacity (OSC) of TWC, mainly due to the degradation of the oxygen storage components and the weakness of the Pd-Ce interaction, is also the cause for TWC deactivation, particularly for the CO oxidation reaction under rich condition. No deactivation of the oxidation reaction of C3H6 by ST, regardless of the catalyst mileages is likely due to the strong oxidative capability of Pd toward hydrocarbons.

Keywords
TWC; Catalyst deactivation; Cerium-zirconium mixed oxide; OSC; Pd-Ce interaction; Pd sintering; Poisoning
First Page Preview
The alteration of the performance of field-aged Pd-based TWCs towards CO and C3H6 oxidation
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 92, Issues 1–2, 19 October 2009, Pages 114–125
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis