Effect of reductive treatments on Pt behavior and NOx storage in lean NOx trap catalysts

Document Type

Conference Proceeding

Publication Date

10-25-2011

Abstract

Lean NOx trap (LNT) catalysts represent a promising approach to meet increasingly stringent NOx emission regulations on diesel and other lean-burn engines. Pt material properties, including dispersion and particle size, are known to be important factors in determining NOx uptake performance, since Pt provides active sites for NO oxidation to NO 2 necessary for storing NOx as nitrates, and for the reduction of nitrates to N2. In this work, the physicochemical properties of Pt in Pt-BaO/Al2O3 LNT catalysts, such as the Pt accessible surface area and particle size, were investigated by using various tools, such as irreversible volumetric H2 chemisorption, high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD), following successive reductive treatments at elevated temperatures. NOx uptake activities were also measured to establish a relationship between the properties of Pt and NOx storage following identical high-temperature reductive treatments. We find that the reductive treatments of Pt-BaO/Al2O3 lean NOx trap catalysts at temperatures up to 500 °C promote a significant increase in NOx uptake explained, in part, by an induced close interaction between Pt and BaO phases in the catalyst, thus enabling facilitation of the NOx storage process. © 2011 Elsevier B.V. All rights reserved.

Identifier

80054865610 (Scopus)

Publication Title

Catalysis Today

External Full Text Location

https://doi.org/10.1016/j.cattod.2011.03.032

ISSN

09205861

First Page

78

Last Page

82

Issue

1

Volume

175

Grant

DE-AC06-76RLO 1830

Fund Ref

U.S. Department of Energy

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