Study of supported palladium catalysis variously heat treated in hydrogen using microactivity testing, transmission electron microscopy, X-ray analysis and the extended X-ray absorption fine structure technique
| Autor: | O. Leonte, M. Bîrjega, M. Georgescu, N. Popescu-Pogrion, P. Pausescu, D. Macovei |
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| Rok vydání: | 1986 |
| Předmět: |
chemistry.chemical_classification
Materials science Hydrogen Extended X-ray absorption fine structure Alkene Hydride Inorganic chemistry chemistry.chemical_element Surfaces and Interfaces General Chemistry Condensed Matter Physics Surfaces Coatings and Films Catalysis chemistry.chemical_compound chemistry Alkadiene Oxidizing agent Materials Chemistry Palladium |
| Zdroj: | Surface and Coatings Technology. 28:347-357 |
| ISSN: | 0257-8972 |
| DOI: | 10.1016/0257-8972(86)90091-5 |
| Popis: | Real regenerated supported palladium (0.5wt.%Pd-LiAl5O8) catalysts used in the hydrogenation of alkenes or alkynes and alkadienes were sintered at high temperatures (300, 500 or 600 °C) in a hydrogen atmosphere, and subjected to alternative treatments in either reducing and/or oxidizing atmospheres. X-ray diffraction analysis indicated hydride formation in the reducing stage, with intermediate compositions ranging between α-PdH and β-PdH, while on using the extended X-ray absorption fine structure technique palladium oxide was observed in catalysts subjected to oxidizing conditions. The statistics of the palladium-crystallite size distributions, as obtained by transmission electron microscopy, showed evidence of sintering and/or redispersion (splitting), as a result of the alternative reducing or oxidizing treatments. The catalytic activity in the alkadiene hydrogenation reaction is influenced by the treatment sequence applied to the regenerated catalysts. |
| Databáze: | OpenAIRE |
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