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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

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

Authors :
O. Leonte
M. Bîrjega
M. Georgescu
N. Popescu-Pogrion
P. Pausescu
D. Macovei
Source :
Surface and Coatings Technology. 28:347-357
Publication Year :
1986
Publisher :
Elsevier BV, 1986.

Abstract

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.

Details

ISSN :
02578972
Volume :
28
Database :
OpenAIRE
Journal :
Surface and Coatings Technology
Accession number :
edsair.doi...........f70e2de4ba812102cb0ef8b293a80b91
Full Text :
https://doi.org/10.1016/0257-8972(86)90091-5