de.mpg.escidoc.pubman.appbase.FacesBean
English
 
Help Guide Disclaimer Contact us Login
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Understanding CeO2 as a Deacon catalyst by probe molecule adsorption and in situ infrared characterisations

MPS-Authors
http://pubman.mpdl.mpg.de/cone/persons/resource/persons21502

Farra,  Ramzi
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

http://pubman.mpdl.mpg.de/cone/persons/resource/persons22257

Wrabetz,  Sabine
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

http://pubman.mpdl.mpg.de/cone/persons/resource/persons22094

Schuster,  Manfred Erwin
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

http://pubman.mpdl.mpg.de/cone/persons/resource/persons22144

Stotz,  Eugen
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

http://pubman.mpdl.mpg.de/cone/persons/resource/persons21595

Hamilton,  Neil
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

http://pubman.mpdl.mpg.de/cone/persons/resource/persons22163

Teschner,  Detre
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

Locator
There are no locators available
Fulltext (public)

c2cp42767b.pdf
(Publisher version), 4MB

Supplementary Material (public)
There is no public supplementary material available
Citation

Farra, R., Wrabetz, S., Schuster, M. E., Stotz, E., Hamilton, N., Amrute, A. P., et al. (2013). Understanding CeO2 as a Deacon catalyst by probe molecule adsorption and in situ infrared characterisations. Physical Chemistry Chemical Physics, 15(10), 3454-3465. doi:10.1039/c2cp42767b.


Cite as: http://hdl.handle.net/11858/00-001M-0000-000E-B003-1
Abstract
CeO2 has been identified as an efficient catalyst for HCl oxidation in the temperature range of 623–723 K provided that the oxygen content in the feed mixture was sufficiently high to avoid bulk chlorination and thus deactivation. Here we characterise ceria in its fresh and post-reaction states by adsorption of CO2, NH3 and CO. Micro-calorimetry, FTIR and TPD experiments are complemented by DFT calculations, which assess adsorption energies and vibrational frequencies. The calculations were performed on the lowest energy surface, CeO2(111), with perfect termination and with various degrees of hydroxylation and/or chlorination. Both experiments and calculations suggest that the basic character of the ceria surface has been eliminated upon reaction in HCl oxidation, indicating that most of the basic lattice O sites are exchanged by chlorine and that the OH groups formed are rather acidic. The density and the strength of surface acidic functions increased significantly upon reaction. An in situ FTIR reaction cell has been designed and constructed to study the evolution of OH group density of the ceria surface during HCl oxidation. The effect of experimental variables, such as pO2, pHCl and temperature, has been investigated. We found that the OH group density positively correlated with the reactivity in the pO2 and temperature series, whereas negative correlation was observed when pHCl was varied. Implications of the above observations to the reaction mechanism are discussed.