Anomalous lattice behavior of vanadium pentaoxide (V₂O₅): X-ray diffraction, inelastic neutron scattering and ab initio lattice dynamics

Abstract

We present the structural and dynamical studies of layered vanadium pentaoxide (V 2 O 5 ). The temperature dependent X-ray diffraction measurements reveal highly anisotropic and anomalous thermal expansion from 12 K to 853 K. The results do not show any evidence of structural phase transition or decomposition of α-V 2 O 5 , contrary to the previous transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) experiments. The inelastic neutron scattering measurements performed up to 673 K corroborate the result of our X-ray diffraction measurements. The analysis of the experimental data is carried out using ab-initio lattice dynamics calculation. The important role of van der-Waals dispersion and Hubbard interactions on the structure and dynamics is revealed through the abinitio calculations. The calculated anisotropic thermal expansion behavior agrees well with temperature dependent X-ray diffraction. The mechanism of anisotropic thermal expansion and anisotropic linear compressibility is discussed in terms of calculated anisotropy in Grüneisen parameters and elastic coefficients. The calculated Gibbs free energy in various phases of V 2 O 5 is used to understand the high pressure and temperature phase diagram of the compound. Softening of elastic constant (C 66 ) with pressure suggests a possibility of shear mechanism for α to β phase transformation under pressure.

Selective Catalytic Oxidation of Lean-H2S Gas Stream to Elemental Sulfur at Lower Temperature

“…These patterns are ascribable to the typical cubic crystal structure of fluorite-type cerium oxide [25]. No additional reflections attributable to V2O5 are detectable, evidencing that the sulfuration of the catalysts completely occurred [26]. Furthermore, there were no peaks detected that related to typical vanadium sulfides (VS2, VS4, V2S3, V3S4) that might have formed following the sulfuration treatment [27].…”

Recent advances in vanadium pentoxide (V2O5) towards related applications in chromogenics and beyond: fundamentals, progress, and perspectives

“…76 Indeed, the edgesharing distorted VO 6 octahedra of eand d-V 2 O 5 are connected by the corner O(1) to form layers with weak V-O(3) and V-O(2) interactions. 63,74,77 For the g-phase, oxygen forms five bonds with two types of vanadium cations resulting in a configuration with two different apex-connected VO 5 pyramids. 65,68,78 The bphase features five nonequivalent oxygen atoms bonded to two octahedrally coordinated vanadium atom types.…”

Electrochromic Performance of V2O5 Thin Films Grown by Spray Pyrolysis

“…The layered structure with orthorhombic symmetry of α-V 2 O 5 can be well adapted to the reversible incorporation of guest Li + ions. As a result, its films have been recognized as the most attractive material for applications in electrochromic devices and in lithium batteries [3][4][5][6][7][8][9][10][11]. The valence state of V atoms is known to be extremely sensitive to the chemical environment, a behavior that can lead to a variety of structures containing different building units and exhibiting different physical properties.…”