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Role of the Oriented Attachment Mechanism in the Phase Transformation of Oxide Nanocrystals
Author(s) -
Ribeiro Caue,
Vila Cristiane,
Milton Elias de Matos José,
Bettini Jefferson,
Longo Elson,
Leite Edson R.
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200700034
Subject(s) - materials science , metastability , annealing (glass) , nanocrystal , transmission electron microscopy , oxide , hydrothermal circulation , chemical physics , phase (matter) , chemical engineering , nanotechnology , crystallography , chemistry , metallurgy , organic chemistry , engineering
Abstract “Bottom‐up” methods to obtain nanocrystals usually result in metastable phases, even in processes carried out at room temperature or under soft annealing conditions. However, stable phases, often associated with anisotropic shapes, are obtained in only a few special cases. In this paper we report on the synthesis of two well‐studied oxides—titanium and zirconium oxide—in the nanometric range, by a novel route based on the decomposition of peroxide complexes of the two metals under hydrothermal soft conditions, obtaining metastable and stable phases in both cases through transformation. High‐resolution transmission electron microscopy analysis reveals the existence of typical defects relating to growth by the oriented attachment mechanism in the stable crystals. The results suggest that the mechanism is associated to the phase transformation of these structures.