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Structural, morphological and acidic changes of nanocrystalline aluminas caused by a controlled humidity atmosphere

Paper ID Volume ID Publish Year Pages File Format Full-Text
43841 45991 2006 8 PDF Available
Title
Structural, morphological and acidic changes of nanocrystalline aluminas caused by a controlled humidity atmosphere
Abstract

The changes in the structural, morphological and acidity properties of nanocrystalline aluminas provoked by hydration under a controlled humidity atmosphere at room temperature were studied. Besides the physical and chemical adsorption of water on the surface, the hydration process causes the formation of aluminum oxy-hydroxide and trihydroxide (boehmite and bayerite). The recalcination of hydrated γ-Al2O3 cannot recuperate the initial acidic properties of the material. The populations of weak to moderate acid sites strongly decrease under recalcination of hydrated aluminas. On the other hand, the stronger acid site populations are not strongly affected by recalcination.

Graphical abstractBesides the multilayer water adsorption on the alumina surface, water vapor can react with transition aluminas, yielding boehmite and bayerite microparticles. Recalcination of these transition aluminas exposed to humidity can only recover their long-range structures, however, is not effective in restoring their initial acidity. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Alumina; Controlled hydration
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Structural, morphological and acidic changes of nanocrystalline aluminas caused by a controlled humidity atmosphere
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 315, 23 November 2006, Pages 44–51
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Price was $35.95
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