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Doped nanosized ceria solid solutions for low temperature soot oxidation: Zirconium versus lanthanum promoters

Paper ID Volume ID Publish Year Pages File Format Full-Text
47086 46458 2010 8 PDF Available
Title
Doped nanosized ceria solid solutions for low temperature soot oxidation: Zirconium versus lanthanum promoters
Abstract

The relative efficacies of zirconium and lanthanum promoters in ceria solid solutions were investigated systematically for low temperature soot oxidation. Thus nanosized CeO2–ZrO2 (CZ, 1:1) and CeO2–La2O3 (CL, 8:2) solid solutions, and a reference CeO2 (C) were synthesized and investigated by means of various characterization techniques namely, XRD, TEM, BET surface area, XPS, UV–vis DRS, Raman and TPR. The catalytic efficiency for oxygen storage/release capacity (OSC) and soot oxidation were evaluated by a thermogravimetric (TG) method. The XRD results suggested formation of solid solutions and TEM studies confirmed nanosized nature of the particles. Raman and XPS measurements disclosed the presence of oxygen vacancies and lattice defects in both CZ and CL samples and these were more prominent in the case of CL sample. XPS studies revealed existence of both Ce3+ and Ce4+ (confirming redox nature), and the concentration of former is relatively higher in CL sample. The CL solid solution exhibited high intense and more resolved O2− → Ce3+ charge transfer transition band compared to CZ in the UV–vis DRS study. TPR measurements indicated a facile reduction of ceria after La3+ incorporation. Activity studies revealed that La3+ doped ceria accelerates the oxidation rate of soot compared to pure ceria and Zr4+ doped ceria. An attempt has been made to explain the enhanced activity of CL sample in terms of active oxygen formation provoked by defective structure of ceria due to the presence of La3+.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ Lanthanum doped ceria solid solutions were explored for soot oxidation. ▶ Design of efficient catalysts for diesel soot combustion is an important research topic. ▶ Formation of nanosized solid solutions and lattice expansion is unveiled for La3+ doped ceria. ▶ Thermal stability of ceria is improved upon La3+ incorporation. ▶ A substantial increase of oxygen vacancies induced more active oxygen for catalysis.

Keywords
Ceria; Ceria–zirconia; Ceria–lanthana; Solid solutions; Catalyst characterization; Soot oxidation; Oxygen storage capacity
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 101, Issues 1–2, 22 November 2010, Pages 101–108
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us