Role of Al and Ti doping in modulating electrical properties of BIVOX system

Abstract

The doubly-doped bismuth vanadate with Al and Ti having formula unit, Bi 2 V 1-x Al x/2 Ti x/2 O 5.5-δ (0.10 ≤ x ≤ 0.25) was synthesized. The specimens were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), differential scanning calorimetric (DSC), UV-Vis, and electrochemical impedance spectroscopy (EIS) for their structural, thermal, optical, and electrical studies. Influence of both dopant cations (Al and Ti) was observed in the gradual stabilization of the tetragonal phase of Bi 2 VO 5.5-δ with dopant amount. A non-uniform grain growth phenomenon was observed up to x = 0.175, with dopant addition. UV-Vis study revealed the comparatively higher order of oxide ion vacancies for the composition x = 0.175. Impedance spectroscopy measurements indicate a significant decrease of both the grain (R g ) and grain boundary resistances (R gb ) with the rise in temperature and the overall resistance is found to be dominated by the grain interior contribution. Enhancement of ionic conductivity was found in all the compositions in the intermediate temperature range as compared to the parent compound, and the single Al-doped system and the highest value were obtained for x = 0.175. vanadate, Bi 2 VO 5.5-δ (where δ denotes the oxygen-ion vacancy) surfaced in the late eighties is of immense importance because of its visibly good ionic conductivity values at relatively low temperature viz. 0.2 S·cm -1 at ~600 ℃ [6]. However, the problem with this compound is of multiple phase transitions (i.e., α↔β and β↔γ between 420 and 450 ℃ and between 540 and 560 ℃ , respectively) and the highest conductivity is found in tetragonal polymorph known as γ-polymorph or phase [6,7]. Therefore, stabilization of this phase at room temperature is essential. The 490

Mesoporous Nano-Sized BiFeVOx.y Phases for Removal of Organic Dyes from Wastewaters by Visible Light Photocatalytic Degradation

“…Moreover, another band can be observed at ~460 cm -1 , ascribed to Bi/Fe-O stretching vibrations. Similar typical FT-IR assignments have also been reported for other BiMeVOxes prepared via the conventional solid synthesis [46]. νs(V-O), and asymmetric νas(V-O) stretching modes of vibration, and asymmetric deformation modes of bending δas(O-V-O) for the vanadate layers, respectively.…”

“…Moreover, another band can be observed at ~460 cm -1 , ascribed to Bi/Fe-O stretching vibrations. Similar typical FT-IR assignments have also been reported for other BiMeVOxes prepared via the conventional solid synthesis [46]. Figure 4 illustrates XPS profiles of the three BiFeVOx.y phases.…”

“…typical FT-IR assignments have also been reported for other BiMeVOxes prepared via the conventional solid synthesis [46]. Figure 4 illustrates XPS profiles of the three BiFeVOx.y phases.…”

New silicon substituted BiMeVOx: synthesis and study of structural properties in relation to ionic conductivity

“…Several references are available in the literature concerning the effect of the substitution of vanadium (V 5+ ) by monovalent, divalent, trivalent, tetravalent, and pentavalent cations. BiMeVO x : Me = Cu 2+ , 9,10 Fe 3+ , 9 Zn 2+ , 10 Co 2+ , 11 Ti 4+ , 12 (Cu 2+ , Ti 4+ ), 13 (Cu 2+ , Al 3+ ), 14 (Al 3+ , Ti 4+ ), 15 P 5+ , 16 and (Ti 4+ , Nb 5+ ). 17 The present work is devoted to the structural analysis of Bi 4 V 2 O 11 as well as to the Si( iv ) doped series Bi 4 V 2− x Si x O 11− δ (0.1 ≤ x ≤ 0.4).…”

Effect of Simultaneous Cu and Nb Doping Bi4v2o11 on Structural and Electrical Properties of Bi4v2−Xcux/2nbx/2o11−3x/4

“…This result is in good agreement with the XRD patterns. In addition, it can be noticed in the FT-IR spectra that some bands move to low or to high frequencies, while others completely disappear from the spectrum as the case of the band at 1052 cm -1 observed in the parent compound for instance [30,33]. The band located at about 512 cm -1 in Bi4V2O11 spectrum, shifts towards the low frequencies as x increases.…”