Surface energy and thermodynamic stability of γ-alumina: Effect of dopants and water

Página do item simplificado
dc.contributor.authorCASTRO, R. H, R.
dc.contributor.authorUSHAKOV, S. V.
dc.contributor.authorGENGEMBRE, L.
dc.contributor.authorGOUVEA, D.
dc.contributor.authorNAVROTSKY, A.
dc.date.accessioned2022-01-12T22:05:37Z
dc.date.available2022-01-12T22:05:37Z
dc.date.issued2006-04-04
dc.description.abstractRetaining large surface areas in alumina powders during high-temperature annealing is a major challenge in applications as catalyst supports and ceramic precursors. This is because the alumina surface area drastically decreases with transformation from the γ modification (defect spinel structure) into the a modification (corundum structure). The objective of this work is to show the thermodynamic basis of using additives, such as Zr and Mg, to control the γ-Al 2O 3 surface and bulk energetics and to manipulate the transformation temperature and surface area. These additives are observed to change the pattern of phase transformation and densification. Direct measurements of heats of solution in a lead borate melt of pure and doped alumina as a function of surface area enabled us to experimentally derive trends in the surface energies of hydroxylated surfaces. Accounting for heats of water adsorption measured on pure and doped alumina surfaces allowed us to delineate the thermodynamic effects of hydration on surface energies. Zr-doped γ-alumina showed a higher energy of the hydroxylated surface than did pure γ-alumina but showed a lower energy of the anhydrous surface. Mg addition does not change surface energies significantly but decreases the energetic instability of the bulk γ phase. © 2006 American Chemical Society.
dc.description.firstpage1867
dc.description.issuenumber7
dc.description.lastpage1872
dc.description.volume18
dc.identifier.citationCASTRO, R. H, R.; USHAKOV, S. V.; GENGEMBRE, L.; GOUVEA, D.; NAVROTSKY, A. Surface energy and thermodynamic stability of γ-alumina: Effect of dopants and water. Chemistry of Materials, v. 18, n. 7, p. 1867-1872, April, 2006.
dc.identifier.doi10.1021/cm052599d
dc.identifier.issn0897-4756
dc.identifier.urihttps://repositorio.fei.edu.br/handle/FEI/4351
dc.relation.ispartofChemistry of Materials
dc.rightsAcesso Restrito
dc.titleSurface energy and thermodynamic stability of γ-alumina: Effect of dopants and water
dc.typeArtigo
fei.scopus.citations95
fei.scopus.eid2-s2.0-33646042870
fei.scopus.subjectAlumina powders
fei.scopus.subjectDopants
fei.scopus.subjectHydroxylated surfaces
fei.scopus.updated2024-07-01
fei.scopus.urlhttps://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=33646042870&origin=inward
Arquivos
Coleções
Artigos