Study of the crystal structure of vanadium doped δ-Bi2O3 and γ-Bi2O3 synthesized at ambient condition by synchrotron radiation XRD

Abstract

This work uses the powder diffraction patterns obtained by synchrotron radiation XRD and the Rieltveld method to analyze the crystal structure of δ-phase and γ-phase bismuth oxide doped with vanadium ions The work is to establish the correlation between the parameters of chemical co- precipitation method and the crystal structure In the part of δ-phase bismuth oxide during the refinement the vanadium ions are placed in the coordinate of bismuth ions in order to acquire the situation inside the lattice while the replacing occur Under the same valence the more the amount of vanadium ions entering the lattice the smaller the lattice parameter will be Also the degree of distortion will be greater Under the same concentration of [V]∕[Bi] vanadium ions with higher valence will replace the bismuth ions easier comparing to lower valence In the part of γ-phase bismuth oxide we follow previous studies about the phase transition between ? phase and γ phase bismuth oxide caused by adding more amounts of vanadium ions And we further discuss the influence caused by vanadium ions entering the crystal lattice The results show there is doping limit for vanadium ions in γ-phase bismuth oxide and vanadium ions will mainly replace the bismuth ions at 2a site slightly replace the bismuth ions at 24f site or cause point defects at 24f site

Date of Award	2020
Original language	English
Supervisor	Yu-chun Wu (Supervisor)