Synthesis of heat storage ceramic λ-Ti₃O₅ using titanium chloride as the starting material

Abstract

This study reports a simple method for synthesizing λ-Ti3O5 through hydrogen reduction calcination using titanium chloride as the starting material. Upon applying 300 MPa pressure, λ-Ti3O5 transitions to β-Ti3O5 as...

Effect of Surface Free Energies and Particle Diameter on the Ti3O5 β → λ Phase Transition Temperature: A Theoretical Study

“…Taking these data into account, we predict λ-Ti 3 O 5 nanoparticles to be more stable than β-Ti 3 O 5 below d crit ≈ 43 ± 5 nm. Spherical λ-Ti 3 O 5 particles published in the literature show diameters of 25 ± 15, 3 57 ± 0.3, 12 30−50, 13 8 ± 2 − 36 ± 15, 10 40 14 and 22 ± 8 nm 15 at ambient conditions. These diameter ranges compare favorably to our theoretical prediction of thermodynamic stability of λ-Ti 3 O 5 nanoparticles below diameters of 50 nm.…”

“…This is in line with experimental observations that a larger particle size lowers the threshold pressure P th for the λ → β phase transition. 12 ■ ASSOCIATED CONTENT * sı Supporting Information…”

“…Nanoparticle size impacts the experimentally observed transition pressure P th , which decreases as the particle size (i.e., particle diameter d) increases. 12 At the same time, the measured phase transition enthalpy ΔH trans decreases as d becomes smaller. 12 While ΔH trans = 13.7 kJ mol −1 was observed for d = 400 nm, 11 for d = 70 nm ΔH trans decreases to 12 ± 1 kJ mol −1 , 2 for d = 57 ± 0.3 nm a ΔH trans of 7.78 ± 0.26 kJ mol −1 was measured, 12 for d = 22 ± 8 a further decrease of ΔH trans to 5.5 kJ mol −1 is observed, 15 and for particles with d = 25 ± 15 nm ΔH trans is only 4.8 kJ mol −1 .…”

“…12 At the same time, the measured phase transition enthalpy ΔH trans decreases as d becomes smaller. 12 While ΔH trans = 13.7 kJ mol −1 was observed for d = 400 nm, 11 for d = 70 nm ΔH trans decreases to 12 ± 1 kJ mol −1 , 2 for d = 57 ± 0.3 nm a ΔH trans of 7.78 ± 0.26 kJ mol −1 was measured, 12 for d = 22 ± 8 a further decrease of ΔH trans to 5.5 kJ mol −1 is observed, 15 and for particles with d = 25 ± 15 nm ΔH trans is only 4.8 kJ mol −1 . 3 In this study we calculate surface energies of all low-index surfaces of both phases at density-functional theory (DFT) level.…”

Phase Transformations of Individual Ti3O5 Nanocrystals Studied by In Situ Electron Microscopy

“…* sı Supporting Information The results from electron diffraction are compared with the values from X-ray diffraction (in parentheses) taken from the literature. 27,28 The…”