Controlled synthesis of bismuth oxide microtetrahedrons and cubes by precipitation in alcohol-Water systems

Bismuth oxide (Bi₂O₃) microtetrahedrons and cubes were synthesised in large quantities by a chemical precipitation and refluxing method with BiCl₃ and NaOH as reactants in alcohol-water systems. The products were characterised by X-ray powder diffraction (XRD), field emission-scanning electron microscope (FESEM), energy-dispersive X-ray spectroscope (EDS) and SEM. XRD analyses showed that the as-prepared Bi₂O₃ was body-centred cubic (bcc) (γ) phase and had a high degree of crystallinity. FESEM and SEM micrographs indicated that tetrahedral Bi₂O₃ with the edge length of 1-5 μm was formed. The morphology of the final products changed into microcubes by increasing the amount of dispersant. The result of the influence of reaction temperature on products revealed that the pure-phase γ-Bi₂O₃, as well as well-defined tetrahedron, was obtained at the temperature ≥75°C.