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Mechanism of stearic acid oxidation over nanocrystalline La1−xA′xBO3La1−xA′xBO3 (A′ = Sr, Ce; B = Co, Mn): The role of oxygen mobility

Paper ID Volume ID Publish Year Pages File Format Full-Text
48351 46503 2008 11 PDF Available
Title
Mechanism of stearic acid oxidation over nanocrystalline La1−xA′xBO3La1−xA′xBO3 (A′ = Sr, Ce; B = Co, Mn): The role of oxygen mobility
Abstract

Catalytic wet air oxidation reaction (CWAO) of stearic acid is carried out in a batch reactor over a series of transition metal-based perovskite samples synthesized by reactive grinding. It is observed that the LaCoO3 sample presents the highest initial activity for this reaction. For comparison, pure and substituted LaMnO3 samples show largely smaller activity in spite of similar specific surface areas. The results show that the accessibility of the low temperature active oxygen (or the reducibility of the transition metal) on the surface of the catalyst conditioned the initial activity of the catalyst. Then, a mechanism involving the reaction of stearic acid molecules with adsorbed oxygen surface site (Co3+O2−) is proposed on the basis of the experimental results. Stearic acid oxidation proceeds via a recurrent decarboxylation process that results in the reduction of cobalt surface sites and formation of surface carbonate species (CO3−). In opposition to what was observed for gas phase oxidation reactions, lanthanum (and Ce or Sr) is found to be massively carbonated during the reaction, leading to the destruction of the perovskite structure and loss of the catalytic activity.

Keywords
Perovskite; Catalytic wet air oxidation; Stearic acid; Catalytic activity; Stability
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Mechanism of stearic acid oxidation over nanocrystalline La1−xA′xBO3La1−xA′xBO3 (A′ = Sr, Ce; B = Co, Mn): The role of oxygen mobility
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 80, Issues 1–2, 15 April 2008, Pages 51–61
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