Nanocrystalline titania pigments were produced by high temperature-forced hydrolysis in a coordinating high-boiling solvent (and water for reference). The effect of synthesis conditions and co-doping with Cr–Sb and V–Sb on particle size and anatase-to-rutile transformation (A → R) was studied by temperature-resolved synchrotron X-ray diffraction. The experiments were performed directly on low concentration (3.5 vol.%) as-synthesized suspensions of titania nanoparticles (up to 230 °C) and on the corresponding dried powders (up to 950 °C). Crystallite size of as-synthesized nano-anatase is around 20 nm (glycol) or 70 nm (water); it exhibits a slow growth rate up to the onset temperature of the A → R. Phase composition and crystallite size are drastically influenced by both synthesis conditions and doping. Synthesis in water resulted in the simultaneous occurrence of anatase and brookite; transformation into rutile begins early but with a slower rate with respect to glycol-based samples. Doping affected the A → R, whose onset temperature in undoped titania (700 °C) was lowered to 650 °C (V–Sb) or prevented up to 950 °C (Cr–Sb). Both (V–Sb) and (Cr–Sb) dopings reduced the volume thermal expansion rate of anatase.

Cruciani, G., Dalconi, M.c., Dondi, M., Meneghini, C., Matteucci, F., Barzanti, A., et al. (2011). Temperature-resolved synchrotron X-ray diffraction of nanocrystalline titania in solvent: the effect of Cr-Sb and V-Sb doping. JOURNAL OF NANOPARTICLE RESEARCH, 13(2), 711-719 [10.1007/s11051-010-0069-1].

Temperature-resolved synchrotron X-ray diffraction of nanocrystalline titania in solvent: the effect of Cr-Sb and V-Sb doping

MENEGHINI, CARLO;
2011-01-01

Abstract

Nanocrystalline titania pigments were produced by high temperature-forced hydrolysis in a coordinating high-boiling solvent (and water for reference). The effect of synthesis conditions and co-doping with Cr–Sb and V–Sb on particle size and anatase-to-rutile transformation (A → R) was studied by temperature-resolved synchrotron X-ray diffraction. The experiments were performed directly on low concentration (3.5 vol.%) as-synthesized suspensions of titania nanoparticles (up to 230 °C) and on the corresponding dried powders (up to 950 °C). Crystallite size of as-synthesized nano-anatase is around 20 nm (glycol) or 70 nm (water); it exhibits a slow growth rate up to the onset temperature of the A → R. Phase composition and crystallite size are drastically influenced by both synthesis conditions and doping. Synthesis in water resulted in the simultaneous occurrence of anatase and brookite; transformation into rutile begins early but with a slower rate with respect to glycol-based samples. Doping affected the A → R, whose onset temperature in undoped titania (700 °C) was lowered to 650 °C (V–Sb) or prevented up to 950 °C (Cr–Sb). Both (V–Sb) and (Cr–Sb) dopings reduced the volume thermal expansion rate of anatase.
Cruciani, G., Dalconi, M.c., Dondi, M., Meneghini, C., Matteucci, F., Barzanti, A., et al. (2011). Temperature-resolved synchrotron X-ray diffraction of nanocrystalline titania in solvent: the effect of Cr-Sb and V-Sb doping. JOURNAL OF NANOPARTICLE RESEARCH, 13(2), 711-719 [10.1007/s11051-010-0069-1].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/120363
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