Study of high temperature phase of titanate nanotubes

Tereza Brunatova¹, Daniela Popelkova², Peter Oleynikov³, Stanislav Danis¹, Xiaodong Zou³, Radomir Kuzel¹

¹Charles University, Faculty of Mathematics and Physics, Dept.of Condensed Matter Physics,
Prague, Czech Republic

²Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague,
Czech Republic
³Berzelii Center EXSELENT on Porous Materials,Stockholm University, Dept. of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden

Titanate nanotubes (Ti-NT) are very promising material with many possible applications in bionedicine, in solar cells, lithium batteries, fuel cells etc [1]. Their structure is not fully undertood and there exists several possible stuctures of Ti-NT [1]. The study of temperature stability of Ti-NT is important because some of possible applications of Ti-NT require heating [1]. By heating of Ti-NT titanate nanowires are obtained. Similarly to Ti-NT several possible phases of titanate nanowires can be discovered as for example: Na₂Ti₆O₁₃ [2], Na₂Ti₃O₇ [2], rutile phase of TiO₂ [2-4], anatase phase of TiO₂ [2], [3], beta TiO₂ [4]. The final structure depends also on the amount of sodium ions if some are present in original Ti-NT sample.

In this contribution, the structure of Ti-NT the structure will be briefly introduced and mainly the structure of titanate nanowires will be discused. The study of titanate nanowires was done by combination of powder X-ray diffraction and 3D rotation electron diffraction. The titanate nanowires were prepared by heating of titanate nanotubes up to 850 C. The structure of final product at 850 C depends on heating conditions and time of heating. We studied four samples - heated in air for 105 minutes, in air for 1000 minutes, in vacuum for 105 minutes and in vacuum for 1000 minutes. The transformation from anatase to rutile is observed in air and vacuum with increasing time of heating. Differences between samples heated in air and vacuum are that in air is observed sodium hexatitanate, anatase and rutile but sample heated in vacuum has only visible diffraction lines from anatase at the beganing of heating.

1. Bavykin DF. V.,Walsh F. C.: Titanate and titania nanotubes, synthesis, properties and application, RSC Publishing, 2010

2. Morgado E., jr, de Abreu M. A. S., Pravia O. R. C., Marinkovic B. A., Jardim P. M., rizzo R.C., Araujo A.S.: A study on the structure and thermal stability of titanate nanotubes as a function of sodium content, Solid State Science, 8, 2006

3. Yu J., Yu H., Cheng B., Trapalis C.: Effects of calcination temperature on the microstructures and photocatalytic activity of titanate nanotubes, Journal of Molecular Catalysis A, 249, 2006

4. Suzuki Y., Yoshikawa S.: Synthesis and thermal analysis of Tio2-deriveted nanotubes prepared by the hydrotherma method, Jounal Material Res., 19, 2004