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Impact of induced chlorine-poisoning on the catalytic behaviour of Ce0.5Zr0.5O2 and Ce0.15Zr0.85O2 in the gas-phase oxidation of chlorinated VOCs

Paper ID Volume ID Publish Year Pages File Format Full-Text
46976 46454 2011 9 PDF Available
Title
Impact of induced chlorine-poisoning on the catalytic behaviour of Ce0.5Zr0.5O2 and Ce0.15Zr0.85O2 in the gas-phase oxidation of chlorinated VOCs
Abstract

The main scope of this work is to evaluate the catalytic stability of two Ce/Zr mixed oxides, namely Ce0.5Zr0.5O2 and Ce0.15Zr0.85O2, in the gas-phase oxidation of 1,2-dichloroethane as a model reaction for chlorinated VOC abatement. In order to simulate an accelerated Cl-poisoning of the catalysts the samples were submitted to a chlorination step with an aqueous solution of HCl at room temperature followed by calcination or by reduction and calcination at mild temperature (550 °C). For comparative purposes pure CeO2 and ZrO2 catalysts were also investigated. It was found that chlorination led to remarkable changes in surface area, acidity and redox properties, as revealed by EDX, N2-physisorption, XRD, Raman spectroscopy, adsorption of pyridine followed by IR, NH3-TPD, H2-TPR and oxygen storage capacity. Interestingly, the balance between negative (significant decrease in surface area, and lower overall acidity and reducibility) and positive (promoted redox properties due to the formation of stable CeOCl patches and generation of new acid sites related to Cl− ions adsorbed on Ce4+ and Zr4+ cations) changes introduced by chlorine incorporation appeared to be effectively counterbalanced. As a result the catalytic behaviour of chlorinated samples was not markedly affected when compared with the corresponding parent samples. Hence, a slightly lower activity was found for CeO2 and Ce0.5Zr0.5O2 while catalytic conversion was somewhat promoted for Ce0.15Zr0.85O2 and ZrO2. Anyway, after chlorination both Ce0.5Zr0.5O2 and Ce0.15Zr0.85O2 exhibited an adequate catalytic performance not only in terms of low-temperature conversion, but also of stability during extended periods of time on stream.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Ce0.15Zr0.85O2 resulted resistant to Cl-poisoning after induced chlorination. ► HCl chlorination led to changes in surface area, and both acid and redox properties. ► Formation of CeOCl and new acid sites were responsible for the stable catalytic behaviour.

Keywords
Chlorinated VOCs oxidation; Ceria–zirconia mixed oxides; Chemical stability; Chlorine poisoning; Catalyst deactivation
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Impact of induced chlorine-poisoning on the catalytic behaviour of Ce0.5Zr0.5O2 and Ce0.15Zr0.85O2 in the gas-phase oxidation of chlorinated VOCs
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 104, Issues 3–4, 18 May 2011, Pages 373–381
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