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Main Title: sReactivation of CeO2‐based Catalysts in the HCl Oxidation Reaction: In situ Quantification of the Degree of Chlorination and Kinetic Modeling
Author(s): Sun, Yu
Hess, Franziska
Djerdj, Igor
Wang, Zheng
Weber, Tim
Guo, Yanglong
Smarsly, Bernd M.
Over, Herbert
Type: Article
Language Code: en
Abstract: Deactivation of CeO2‐based catalysts in the HCl oxidation reaction proceeds via selective bulk chlorination of the active CeO2 component to form CeCl3×nH2O. We study the reactivation of two bulk‐chlorinated CeO2‐based Deacon catalysts by oxygen treatment at 430 °C, namely pure CeO2 and 20 mol % of CeO2 supported on preformed ZrO2 particles (20CeO2@ZrO2), with a dedicated experiment. In the flow reactor setup we determine in‐situ the degree of chlorination of the catalyst by quantifying down‐stream with in‐situ UV‐Vis spectroscopy the total amount of chlorine in the catalyst that is exchanged by reoxidation at 430 °C. The activity of deactivated 20CeO2@ZrO2 can be fully restored by oxygen exposure at 430 °C, while that of pure CeO2 declines steadily. Since the UV‐Vis analytics is fast and sensitive, we can follow the kinetics of reoxidation. To rationalize the observed kinetics, we develop a modified Johnson‐Mehl‐Avrami‐Kolmogorov (JMAK) model based on a nucleation‐and‐growth approach for the reoxidation of the catalyst starting from the chlorinated phase. The fast reoxidation kinetics of chlorinated 20CeO2@ZrO2 is traced to a fast nucleation rate.
Issue Date: 9-Sep-2020
Date Available: 7-Jan-2021
DDC Class: 540 Chemie und zugeordnete Wissenschaften
Subject(s): Deacon reaction
in situ experiment
Avrami modelling
Journal Title: ChemCatChem
Publisher: Wiley
Publisher Place: New York, NY
Volume: 12
Issue: 21
Publisher DOI: 10.1002/cctc.202000907
Page Start: 5511
Page End: 5522
EISSN: 1867-3899
ISSN: 1867-3880
Appears in Collections:FG Chemische Katalyse » Publications

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