Hydrogen adsorption kinetics on Pd/Ce0.8Zr0.2O2
| Autor: | Paolo Fornasiero, Fabiana C. Gennari, C. Neyertz, G. Meyer, Tiziano Montini |
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| Přispěvatelé: | GENNARI F., C, Neyertz, C, Mayer, G, Montini, Tiziano, Fornasiero, Paolo |
| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: |
Models
Molecular Hydrogen Spectrophotometry Infrared Inorganic chemistry Kinetics Oxygene Oxide General Physics and Astronomy Infrared spectroscopy chemistry.chemical_element Oxygen Catalysis chemistry.chemical_compound Adsorption Computer Simulation Physical and Theoretical Chemistry computer.programming_language ceria-zirconia hydrogen adsorption Chemistry Hydrogen Bonding Partial pressure Cerium Models Chemical kinetics Zirconium computer Palladium |
| Popis: | Hydrogen adsorption on Pd/Ce(0.8)Zr(0.2)O(2) was studied by temperature-programmed reduction, volumetric measurements and IR spectroscopy. Hydrogen uptake and reduction rate at 353 K are strongly dependent on the hydrogen pressure. At relatively high hydrogen partial pressure, reduction involves PdO, the surface and a significant fraction of the bulk of the ceria based oxide. Formation of oxygen vacancies even at low temperature (373 K) is observed. The hydrogen adsorption process is mainly irreversible, as is shown by an increase in the (2)F(5/2)--(2)F(7/2) electronic transition of Ce(3+) with hydrogen pressure and surface dehydroxylation. This "severe" reduction has a negative effect on the subsequent hydrogen adsorption capability. The decrease of hydrogen uptake capacity and rate during adsorption can be associated with the partial loss of superficial OH and the presence of Ce(3+), which deactivates Pd electronically. |
| Databáze: | OpenAIRE |
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