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Near-ambient X-ray photoemission spectroscopy and kinetic approach to the mechanism of carbon monoxide oxidation over lanthanum substituted cobaltites

Paper ID Volume ID Publish Year Pages File Format Full-Text
51285 46837 2009 5 PDF Available
Title
Near-ambient X-ray photoemission spectroscopy and kinetic approach to the mechanism of carbon monoxide oxidation over lanthanum substituted cobaltites
Abstract

We have studied the oxidation of carbon monoxide over a lanthanum substituted perovskite (La0.5Sr0.5CoO3−d) catalyst prepared by spray pyrolysis. Under the assumption of a first-order kinetics mechanism for CO, it has been found that the activation energy barrier of the reaction changes from ∼80 to ∼40 kJ mol−1 at a threshold temperature of ca. 320 °C. In situ XPS near-ambient pressure (∼0.2 torr) shows that the gas phase oxygen concentration over the sample decreases sharply at ca. 300 °C. These two observations suggest that the oxidation of CO undergoes a change of mechanism at temperatures higher than 300 °C.

Keywords
Near-ambient XPS; CO oxidation; Perovskites
First Page Preview
Near-ambient X-ray photoemission spectroscopy and kinetic approach to the mechanism of carbon monoxide oxidation over lanthanum substituted cobaltites
Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Communications - Volume 10, Issue 14, 25 August 2009, Pages 1898–1902
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis