Analysis of Anhydrous and Hydrated Surface Energies of gamma-Al2O3 by Water Adsorption Microcalorimetry

Autor:	Ricardo H. R. Castro, Dat V. Quach
Rok vydání:	2012
Předmět:	Isothermal microcalorimetry Chemistry Thermodynamics Sintering Crystal growth Molecular configuration Surface energy Surfaces Coatings and Films Electronic Optical and Magnetic Materials Crystallography General Energy Adsorption Anhydrous Relative humidity Physical and Theoretical Chemistry
Zdroj:	The Journal of Physical Chemistry C. 116:24726-24733
ISSN:	1932-7455 1932-7447
DOI:	10.1021/jp309319j
Popis:	Surface energies have postulated importance to catalysis, crystal growth, sintering, polymorphism, and many other fields. This importance is even more critical when dealing with nanostructured materials, where the surface-to-volume ratio is considerably higher and the surface term accounts for a much larger fraction of the total free energy. Here we present a novel approach to experimentally assess the average anhydrous and hydrated surface energies of oxides, and used the method to determine the surface energy of gamma-alumina. The method uses a water adsorption setup combined with a microcalorimeter where the heat of adsorption can be monitored as a function of the adsorbed amount. Maintaining a closed system, the approach enables the correlation of the molecular configuration of absorbed water with the thermodynamic data, and hence the definition of the point where a liquid water configuration exists (at high relative humidity). This information allows the calculation of the surface energy at room temp...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::d4220741d247500a8eaa91e65430c7c4 https://doi.org/10.1021/jp309319j Zobrazit plný text záznamu