Atomic Mechanism of Predictable Phase Transition in Dual‐Phase H₂Ti₃O₇/TiO₂ (B) Nanofiber: An In Situ Heating TEM Investigation

Abstract

The phase transition from H(2)Ti(3)O(7) to TiO(2) (B) in a 1D single nanocrystal of H(2)Ti(3)O(7) was observed by in situ heating in a transmission electron microscope experimentally. The results indicate a typical monoclinic-to-monoclinic crystallographic orientation relationship between the two phases. Moreover, the fundamental building blocks and invariant deformation element model were both adopted to reveal the atomic mechanism and predict the crystallographic orientation relationship quantitatively for the phase transition. The prediction was precisely consistent with TEM results.

Diverse Interface Structures in TiO2 (B)/Anatase Dual‐Phase Nanofibers

“…In order to obtain the TB/TA nanofibers accurately, the X‐ray diffraction (XRD) spectra are first collected to illustrate the phase evolution process under different calcination temperatures, as shown in Figure . Previous research works suggest the phase transformation path from the hydrothermally grown H 2 Ti 3 O 7 is H 2 Ti 3 O 7 → TiO 2 (B) → Anatase . The experimental results of this study still consistent with the above rules.…”

“…After calcination at 500 °C, the products totally transform to TB phase (JCPDS No. #46‐1238) through the dehydration between the TiO 6 octahedra slabs . Continue to increase the calcination temperature to 600 °C, the phase composition of the products still remains pure TB phase with the slightly increased peak intensity, indicating the enhanced crystallization with the increasing of temperature.…”

“…During the preparation of the TB/TA nanocomposites, one of the most important factors of the interface structures obtained by phase transformation is the crystallographic features, including orientation relationships (OR), habit plane (HP), and growth direction (GD) etc. Unlike the situation of metal/TiO 2 system, the interfaces generated through phase transformation are usually specific crystallographic planes . Therefore, the coherency, OR, and defects distribution of the interfaces are of great important to the final properties.…”

A DFT +Ustudy on structural, electronic, vibrational and thermodynamic properties of TiO2polymorphs and hydrogen titanate: tuning the Hubbard ‘U-term’

“…TiO 2 polymorphs have the same behavior; hydrogen titanate does not experience any significant volumetric change when temperature is increased. Instead, a volume contraction is observed near 200 K which is correlated to the presence of several imaginary vibrational modes, that only appear for the cell volumes associated to that temperature, but that does not appear for the equilibrium values associated at 0 K. This fact could be connected to a possible phase transformation from hydrogen titanate to TiO 2 (B) in the same range of temperatures [44]. Anatase and rutile lead to bigger volumetric variations.…”

Interpretation of the vacancy-ordering controlled growth morphology of Hg5In2Te8 precipitates in Hg3In2Te6 single crystals by TEM observation and crystallographic calculation

“…Among these models, the IDE model based on the invariant line theory is considered to be a relatively simplified model as only one-step rotation is needed during the calculation. In addition, this model has been proved on various material systems [41], including nanomaterials [42,43]. Therefore, it is employed to interpret the growth morphology of the Hg 5 In 2 Te 8 precipitates during the evolved phase transitions in present work.…”