Molten salt syntheses of alkali metal titanates
Résumé
ubmicrometer dispersions of rod-like alkali metal titanates were prepd. by the flux method, from the reaction of TiOSO4 or TiO2 precursors in molten alkali metal nitrates, doped with carbonates or hydroxides. Mono-, di-, tetra-, and hexatitanates are formed as a function of the precursor nature and the melt compn. As a rule, in these syntheses poorly cryst. or amorphous solids are obtained, showing the structure of polytitanates on the nanoscopic level. Lamellar potassium hexatitanate can be exchanged by action of a dild. acid, leading to protonic form, free from the alkali metal but retaining initial morphol. Reactivity of TiOSO4 and TiO2 in molten alkali metal nitrates and their mixts. with the corresponding carbonates was studied by mass spectrometry of the gases evolved during heating of the reaction mixts. For both pure and doped nitrates it changes in the expected row Li>Na>K, following the melts oxobasicity sequence