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Nanostructuring Titania: Control over Nanocrystal Structure, Size, Shape, and Organization
Author(s) -
Chemseddine Abdelkrim,
Moritz Thomas
Publication year - 1999
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(19990202)1999:2<235::aid-ejic235>3.0.co;2-n
Subject(s) - anatase , alkoxide , nanocrystal , tetramethylammonium hydroxide , chemistry , titanium , chemical engineering , high resolution transmission electron microscopy , brookite , nanotechnology , tetramethylammonium , self assembly , inorganic chemistry , materials science , organic chemistry , catalysis , transmission electron microscopy , photocatalysis , ion , engineering
Control over crystal structure, size, shape, and organization of TiO 2 nanocrystals has been achieved by means of wet chemistry. Hydrolysis and polycondensation of titanium alkoxide [Ti(OR) 4 ] has been performed in the presence of tetramethylammonium hydroxide (Me 4 NOH). This base both catalyzes the reaction and provides an organic cation that stabilizes the anatase polyanionic cores formed in this medium. These anatase clusters are organized so as to favour self‐assembly into intermediate nanocrystals, which, in turn, self‐assemble into superlattices. This self‐assembling process has been exploited for the processing of highly structured titania films. Furthermore, larger anatase TiO 2 nanocrystals of different sizes and shapes have been obtained by adjusting the relative concentrations of titanium alkoxide and Me 4 NOH, the reaction temperature, and the pressure. HRTEM, XRD, and EXAFS have been used to characterize the various samples and to elucidate the growth of titania anatase. Our observations are in accordance with theoretically predicted condensation and growth pathways. The formation of mesoscopic structures through a self‐assembling process of the multiply charged polytitanate anions in the presence of Me 4 N + is also discussed.