Probing the Local Structure and Phase Transitions of Bi₄V₂O₁₁‐Based Fast Ionic Conductors by Combined Raman and XRD Studies

Abstract

In this article, we report the structural phase transitions in Bi 4 V 2 O 11 as observed from temperature-dependent Raman scattering and X-ray diffraction measurements. Four different types of highly disordered coordination polyhedra around the vanadium atoms with large dispersion of V-O bond lengths are observed in Bi 4 V 2 O 11 at ambient temperature. The observed V-O bond lengths could be grouped into two categories, viz. shorter <1.7 A and longer >1.7 A. The Raman modes of Bi 4 V 2 O 11 could be assigned to vibration of these bonds and V-O-V linkages. We could correlate the difference in degree of anharmonicity of the phonon modes with temperature to differences in V-O bond strength. The local structure of vanadium-oxygen network in Bi 4 V 1.8 Cu 0.2 O 10.7 was also obtained by similar studies. The effect of highly disordered anion sublattice in the doped compound is reflected in the broadening of the Raman modes.

An Amorphous Noble‐Metal‐Free Electrocatalyst that Enables Nitrogen Fixation under Ambient Conditions

“…After washing with H 2 O 2 that can dissolve amorphous V 2 O 5 , the undamaged morphology and amorphous structure of BVC‐A accurately determine that the amorphous component corresponds to Bi 4 V 2 O 11 phase rather than the composite of Bi 2 O 3 and V 2 O 5 (Supporting Information, Figure S8) . Besides, the Raman band of BVC‐A locates at nearly the same position when taking crystalline Bi 4 V 2 O 11 as reference, which confirms the construction of amorphous Bi 4 V 2 O 11 as correlated with the Raman spectra (Supporting Information, Figure S5) . A high‐resolution TEM (HRTEM) image shows that CeO 2 nanocrystals with a size of about 3 nm are well‐dispersed in BVC‐A nanofibers (Figure e,f).…”

Realizing nanosized interfacial contact via constructing BiVO4/Bi4V2O11 element-copied heterojunction nanofibres for superior photocatalytic properties

“…Above results confirm that interfacial chemical bonding is formed to construct heterojunction between BiVO 4 nanofibres and embedded Bi 4 V 2 O 11 nanocrystals, which could be an expedite interface for promoting the interfacial photoinduced carriers transfer. increases [34,35]. Interestingly, taking BVO-0 as a reference, the Raman band shifting in BVO-1 could result from the formation of nanosized heterojunction, because the nanosized interfacial contact might cause intrinsic stresses on the crystal structure and change the periodicity of the lattice [36,37].…”

Effects of catalyst crystal structure on the oxidation of propene to acrolein

“…Bi 4 V 2 O 11 is stable in the ␣-phase polymorph for temperatures of below 723 K, and therefore the diffraction pattern for this material is assigned to ␣-Bi 4 V 2 O 11 . For Bi 4 V 2-x Mo x O 11+x/2 , where x = 0.5 and 0.1, the material is taken to be in the ␤-phase based on previous studies showing this phase to be stable for 0.05 < x < 0.225 [24,27]. Table 1 Kinetics and physical properties of Bi4V2-xMoxO 11+x/2 .…”