Topics in Catalysis

, Volume 55, Issue 1–2, pp 70–77

Enhanced High Temperature Performance of MgAl2O4-Supported Pt–BaO Lean NOx Trap Catalysts

  • Ja Hun Kwak
  • Do Heui Kim
  • János Szanyi
  • Sung June Cho
  • Charles H. F. Peden
Original Paper

Abstract

The structural and chemical characteristics of Pt/BaO lean NOx trap (LNT) catalysts supported on γ-Al2O3 and MgAl2O4 are compared in this study. The Pt–BaO/MgAl2O4 sample shows relatively low NOx uptake at temperatures below 300 °C, and the temperature of maximum NOx uptake (Tmax) is shifted to 350 °C in comparison to that of Pt–BaO/Al2O3 (Tmax ~ 250 °C). More importantly, the NOx uptake over the MgAl2O4-supported catalyst at 350 °C is twice that of the alumina-based one. The shift toward the higher temperature NOx uptake is explained by the larger interfacial area between Pt and BaO, due to smaller Pt clusters as evidenced by TEM and Pt L3 EXAFS. In situ TR-XRD results demonstrate that the formation of a BaAl2O4 phase in the BaO/MgAl2O4 LNT catalyst occurs at a temperature about 100 °C higher than on BaO/Al2O3, which may also represent a beneficial attribute of the BaO/MgAl2O4 LNT with respect to catalyst stability.

Keywords

Magnesium aluminate LNT Pt cluster Barium oxide NOx 

Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • Ja Hun Kwak
    • 1
  • Do Heui Kim
    • 1
    • 2
  • János Szanyi
    • 1
  • Sung June Cho
    • 3
  • Charles H. F. Peden
    • 1
  1. 1.Institute for Integrated CatalysisPacific Northwest National LaboratoryRichland USA
  2. 2.School of Chemical and Biological EngineeringInstitute of Chemical Process, Seoul National UniversitySeoulRepublic of Korea
  3. 3.Department of Applied Chemical Engineering, Center for Functional Nano Fine Chemicals (BK21 Program)Chonnam National UniversityGwangjuRepublic of Korea

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