Electrochemical Synthesis of Titanium Oxide Nanopowders in a Molten Mixture of Alkali Chlorides and Nitrates

• Published in: Russian metallurgy Metally 2021-08, Vol.2021 (8), p.1029-1035
• Main Authors: Elshina, L. A., Kvashnichev, A. G., Pelegov, D. V.
• Format: Article
• Language: English
• Subjects: Anatase; Anodic polarization; Argon; Brookite; Cesium; Chemical synthesis; Chemistry and Materials Science; Materials Science; Metallic Materials; Microparticles; Nanoparticles; Nitrates; Oxidation; Particle size; Phase composition; Raman spectroscopy; Rutile; Scanning electron microscopy; Sodium chloride; Sodium nitrates; Spectroscopic analysis; Spectrum analysis; Temperature; Titanium; Titanium dioxide; Titanium oxides; X-ray diffraction
• ISSN: 0036-0295; 1555-6255; 1531-8648
• DOI: 10.1134/S0036029521080061

Titanium oxide nanoparticles are synthesized in a molten mixture of alkali chlorides and nitrates. X-ray diffraction analysis, Raman spectroscopy, and scanning electron microscopy are used to identify the oxide powders. Titanium oxides of various modifications and compositions are synthesized by anodic polarization of high-purity titanium in a molten eutectic mixture of cesium and sodium chlorides containing 5 wt % sodium nitrate. Polarization is carried out under galvanostatic conditions at a current density of 3.5 mA/cm 2 and a temperature of 540–700°C in an argon atmosphere. The phase composition of the oxidation products depends on the synthesis temperature. The particle size is controlled by varying the density and temperature. X-ray diffraction analysis and Raman spectroscopy show that the sample synthesized at a temperature of 540°C is single-phase and consists of Cs 1.36 Ti 6.64 O 16 . The samples synthesized at temperatures of 600 and 650°C form the TiO 2 phase in mixed anatase and rutile modifications. The sample synthesized at a temperature of 700°C consists of TiO 2 titanium dioxide (rutile and brookite modification) and NaTi 8 O 13 . According to scanning electron microscopy, the particle size decreases when the synthesis temperature increases. The sample synthesized at a temperature of 540°C and annealed at a temperature of 200°C contains a mixture of the nano- and microparticles of cesium trititanate (over 50 nm). The titanium dioxide particle size is 20 nm in the sample synthesized at a temperature of 600°C and is 10–20 nm in the samples synthesized at temperatures of 650 and 700°C.