In situ observation of structural changes in polycrystalline silver catalysts by environmental scanning electron microscopy
Data(s) |
1998
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Resumo |
Morphology changes induced in polycrystalline silver catalysts as a result of heating in either oxygen, water or oxygen-methanol atmospheres have been investigated by environmental scanning electron microscopy (ESEM), FT-Raman spectroscopy and temperature programmed desorption (TPD). The silver catalyst of interest consisted of two distinct particle types, one of which contained a significant concentration of sub-surface hydroxy species (in addition to surface adsorbed atomic oxygen). Heating the sample to 663 K resulted in the production of 'pin-holes' in the silver structure as a consequence of near-surface explosions caused by sub-surface hydroxy recombination. Furthermore, 'pin-holes' were predominantly found in the vicinity of surface defects, such as platelets and edge structures. Reaction between methanol and oxygen also resulted in the formation of 'pin-holes' in the silver surface, which were inherently associated with the catalytic process. A reaction mechanism is suggested that involves the interaction of methanol with sub-surface oxygen species to form sub-surface hydroxy groups. The sub-surface hydroxy species subsequently erupt through the silver surface to again produce 'pin-holes'. |
Formato |
application/pdf |
Identificador | |
Publicador |
Royal Society of Chemistry |
Relação |
http://eprints.qut.edu.au/62039/1/J._Chem._Soc.%2C_Faraday_Trans.%2C_1998%2C94%2C_2015-2023.pdf DOI:10.1039/A802674B Millar, Graeme J., Nelson, Megan L., & Uwins, Philippa J.R. (1998) In situ observation of structural changes in polycrystalline silver catalysts by environmental scanning electron microscopy. Journal of the Chemical Society, Faraday Transactions, 94(14), pp. 2015-2023. |
Direitos |
Copyright 1998 Royal Society of Chemistry Restrictions on further re-use and further distribution |
Fonte |
School of Chemistry, Physics & Mechanical Engineering; Institute for Future Environments; Science & Engineering Faculty |
Palavras-Chave | #030601 Catalysis and Mechanisms of Reactions #silver #catalyst #formaldehyde #methanol #ESEM |
Tipo |
Journal Article |