TY - JOUR
T1 - Hydrothermal synthesis of brookite-type titanium dioxide with snowflake-like nanostructures using a water-soluble citratoperoxotitanate complex
AU - Kobayashi, Makoto
AU - Petrykin, Valery
AU - Tomita, Koji
AU - Kakihana, Masato
N1 - Funding Information:
This work was supported in part by a Grant-in-Aid for Scientific Research (No. 22107002 ) on Innovative Areas of “Fusion Materials: Creative Development of Materials and Exploration of Their Function through Molecular Control” (No. 2206 ) from the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) . M. Kobayashi acknowledges the support of a Research Fellowship for Young Scientists from the Japan Society for the Promotion of Science (JSPS).
PY - 2011/12/15
Y1 - 2011/12/15
N2 - Hydrothermal synthesis of brookite-type titanium dioxide was performed with excellent reproducibility using an aqueous NH3 solution of a water-soluble citratoperoxotitanate (CPT) complex. X-ray diffraction confirmed that the brookite phase was formed by hydrothermal treatment of the CPT complex in NH3 solution with a concentration of more than 6.5 wt%, whereas single phase anatase was obtained when distilled water without any additives was applied as the solvent. The aspect ratios of the obtained rod-like brookite particles increased from 5 up to 20 with an increase of the NH3 concentration. Transmission electron microscopy and selected area electron diffraction measurements provided evidence that the growth of the brookite particles is along the c-axis. Hydrothermal treatment of the CPT complex at high NH3 concentrations resulted in the formation of agglomerated brookite particles with unusual shapes, where many rod-like particles were branched around a somewhat longer central particle, and the side view of the agglomerated particles revealed two-dimensional crystal growth within a given restricted plane. The multi-needle agglomerate of particles was snowflake shaped. The reason for the formation of brookite with this unique morphology may be attributed to an intrinsic character of the CPT complex itself, although the mechanism is yet to be clarified.
AB - Hydrothermal synthesis of brookite-type titanium dioxide was performed with excellent reproducibility using an aqueous NH3 solution of a water-soluble citratoperoxotitanate (CPT) complex. X-ray diffraction confirmed that the brookite phase was formed by hydrothermal treatment of the CPT complex in NH3 solution with a concentration of more than 6.5 wt%, whereas single phase anatase was obtained when distilled water without any additives was applied as the solvent. The aspect ratios of the obtained rod-like brookite particles increased from 5 up to 20 with an increase of the NH3 concentration. Transmission electron microscopy and selected area electron diffraction measurements provided evidence that the growth of the brookite particles is along the c-axis. Hydrothermal treatment of the CPT complex at high NH3 concentrations resulted in the formation of agglomerated brookite particles with unusual shapes, where many rod-like particles were branched around a somewhat longer central particle, and the side view of the agglomerated particles revealed two-dimensional crystal growth within a given restricted plane. The multi-needle agglomerate of particles was snowflake shaped. The reason for the formation of brookite with this unique morphology may be attributed to an intrinsic character of the CPT complex itself, although the mechanism is yet to be clarified.
KW - A1. Crystal morphology
KW - A1. Nanostructures
KW - A2. Growth from solutions
KW - A2. Hydrothermal crystal growth
KW - B1. Nanomaterials
KW - B1. Titanium compounds
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U2 - 10.1016/j.jcrysgro.2011.09.046
DO - 10.1016/j.jcrysgro.2011.09.046
M3 - Article
AN - SCOPUS:81855194311
VL - 337
SP - 30
EP - 37
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
SN - 0022-0248
IS - 1
ER -