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Snapshots of the Formation of NaTi 3 O 6 (OH)·2H 2 O Nanowires: A Time‐Resolved XRD/HRTEM Study
Author(s) -
Koll Dominik,
Andrusenko Iryna,
Mugnaioli Enrico,
Birkel Alexander,
Panthöfer Martin,
Kolb Ute,
Tremel Wolfgang
Publication year - 2013
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201300411
Subject(s) - high resolution transmission electron microscopy , selected area diffraction , nanowire , materials science , nanosheet , transmission electron microscopy , chemical engineering , hydrothermal synthesis , dissolution , crystallography , titanate , nanotechnology , hydrothermal circulation , chemistry , ceramic , engineering , composite material
Layered titanates are important intermediates during the formation of TiO 2 ‐related nanostructures in hot concentrated base solution. Microwave‐assisted hydrothermal techniques allow a time‐resolved ex‐situ analysis of the reaction in one‐minute intervals by rapid heating and quenching followed by separation and structure analysis of the intermediates. By a combination of powder X‐ray diffraction, high resolution electron microscopy (HRTEM), and selected area electron diffraction (SAED) the individual stages of the reaction could be identified. Sodium titanate nanosheets are formed within several minutes by digesting the crystalline TiO 2 ‐P25 precursor in NaOH. These nanosheets with a low sodium content form flake‐like aggregates. Subsequently, these nanosheet intermediates form nanoscrolls and/or nanotubes, which transform in the next step to NaTi 3 O 6 (OH) · 2H 2 O nanowires by reaction with NaOH via an oriented attachment of nanotubes from solution. The NaTi 3 O 6 (OH) · 2H 2 O nanowires grow at the expense of the nanotubes and form an ordered structure via dissolution‐recrystallization equilibria between solid NaTi 3 O 6 (OH) · 2H 2 O and soluble titanate species.