TY - JOUR
T1 - Morphology, chemical composition and phase transformation of hydrothermal derived sodium Titanate
AU - Li, Meng Jung
AU - Chi, Zuo Yun
AU - Wu, Yu Chun
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012/10
Y1 - 2012/10
N2 - This study intends to clarify the discrepancies on the effect of precursor size, chemical composition, and thermal behavior of Na-titanate obtained through a conventional hydrothermal reaction of anatase in a highly concentrated aqueous NaOH solution. According to experimental results, as well as that presented in related literatures, ultrafine anatase precursor favors nanofiber formation, whereas larger-particle anatase precursor forms nanotubes. The formation mechanism, in correlation with the precursor size and the resulting morphology of the obtained titanate product, is described in detail. According to X-ray Diffraction and Raman analyses, the as-formed Na-titanate is considered a quasi-disordered structure that allows the occupation of a wide range of Na into the titanate structure. An increased Na/Ti ratio is observed with increased temperature, which simultaneously results in a distortion of the titanate structure. Moreover, the as-synthesized Na-titanate is thermally unstable and tends to degrade into amorphous clusters after heat treatment at 300°C. Rod-like Na 2Ti 6O 13 is recrystallized from the amorphous cluster at 700°C-800°C and becomes plate-like after annealing at 900°C via a parallel assembly of Na 2Ti 6O 13 rods. An additional Na 2Ti 3O 7 phase appears at high temperatures, exhibiting a relatively higher Na/Ti ratio.
AB - This study intends to clarify the discrepancies on the effect of precursor size, chemical composition, and thermal behavior of Na-titanate obtained through a conventional hydrothermal reaction of anatase in a highly concentrated aqueous NaOH solution. According to experimental results, as well as that presented in related literatures, ultrafine anatase precursor favors nanofiber formation, whereas larger-particle anatase precursor forms nanotubes. The formation mechanism, in correlation with the precursor size and the resulting morphology of the obtained titanate product, is described in detail. According to X-ray Diffraction and Raman analyses, the as-formed Na-titanate is considered a quasi-disordered structure that allows the occupation of a wide range of Na into the titanate structure. An increased Na/Ti ratio is observed with increased temperature, which simultaneously results in a distortion of the titanate structure. Moreover, the as-synthesized Na-titanate is thermally unstable and tends to degrade into amorphous clusters after heat treatment at 300°C. Rod-like Na 2Ti 6O 13 is recrystallized from the amorphous cluster at 700°C-800°C and becomes plate-like after annealing at 900°C via a parallel assembly of Na 2Ti 6O 13 rods. An additional Na 2Ti 3O 7 phase appears at high temperatures, exhibiting a relatively higher Na/Ti ratio.
UR - http://www.scopus.com/inward/record.url?scp=84867102148&partnerID=8YFLogxK
U2 - 10.1111/j.1551-2916.2012.05330.x
DO - 10.1111/j.1551-2916.2012.05330.x
M3 - Journal article
AN - SCOPUS:84867102148
SN - 0002-7820
VL - 95
SP - 3297
EP - 3304
JO - Journal of the American Ceramic Society
JF - Journal of the American Ceramic Society
IS - 10
ER -