Synthesis and characterisation of bismuth(III) vanadate

• Published in: Journal of molecular structure Vol. 744; pp. 535 - 540
• Main Authors: Gotić, M., Musić, S., Ivanda, M., Šoufek, M., Popović, S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 03.06.2005
• Subjects: Bismuth vanadate; BiVO 4; Electron microscopy; FT-IR; Hydrothermal synthesis; Raman; Solid state; XRD; ‘Wet’ precipitation; Solid state; Hydrothermal synthesis; Bismuth vanadate; FT-IR; Raman; BiVO 4; XRD; Electron microscopy; ‘Wet’ precipitation
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2004.10.075

Modified hydrothermal and ‘wet’ precipitation routes at room temperature were employed to synthesise pure monoclinic BiVO 4 powders of varying particle morphologies. Monoclinic BiVO 4 powder was also prepared by a solid-state reaction at 700°C. Depending on the synthesis conditions, the colour of BiVO 4 varies from inhomogeneously yellow–brown to homogeneously and intensive lemon yellow. BiVO 4 prepared by solid-state reaction consisted of large compact particles about 15 μm in size and of irregular shape. At higher magnification, the formation of domains with smooth terrace-like surfaces was observed. These domains ended with well-defined walls, and the edges of these walls were relatively very sharp. BiVO 4 synthesised by the hydrothermal and an aqueous process at RT consisted of smaller particles (0.3–1.2 μm) and of much bigger regular crystals with a well-defined crystal habit. A continuous shift of the most intense Raman band to lower wavenumbers reveals that the average short range symmetry of the VO 4 tetrahedra becomes more regular. The values of FWHM for the same Raman band increase from sample prepared by solid-state reaction to sample obtained at RT. The Raman results suggested that a sample prepared at high temperature consisted of less symmetric VO 4 tetrahedra than samples prepared at low temperature and that the high-temperature sample showed better crystallinity with less defects than the samples prepared by an aqueous process under mild conditions. FT-IR spectra showed main features typical of the vanadates of other metal(3+) cations. However, the position of IR bands recorded for BiVO 4 depended on the synthesis route.