Metal Titanates

Alkali Metal Titanates. Alkali metatitanates may be prepared by fusion of titanium oxide with the appropriate alkah metal carbonate or hydroxide. Representative alkah metal titanates ate hsted in Table 14. The alkah metal titanates tend to be more reactive and less stable than the other titanates, eg, they dissolve relatively easily in dilute acids. 

Composite Oxyalkoxides. Composite oxyalkoxides can be prepared by reaction of tetraalkyl titanates and alkaline-earth metal hydroxides. These oxyalkoxides and their derivatives can be hydroly2ed and thermally decomposed to give alkaline-earth metal titanates such as barium titanate (150). 

Barium titanate thin films can be deposited on various substances by treating with an aqueous solution containing barium salts and an alkanolamine-modifted titanate such as TYZOR TE (151). In a similar fashion, reaction of a tetraalkyl titanate with an alkah metal hydroxide, such as potassium hydroxide, gives oxyalkoxide derivatives (KTi O(OR) ), which can be further processed to give alkali metal titanate powders, films, and fibers (152—155). The fibers can be used as adsorbents for radioactive metals such as cesium, strontium, and uranium (156). 

Inoue, Y., Kubokawa, T., and Sato, K., Photocatalytic activity of alkali-metal titanates combined with Ru in decomposition of water, /. Phys. Chem., 95, 4059,1991. 

Alkali-metal salts, 24 145 Alkali-metal tellurides, 24 417 Alkali-metal thermal electric conversion (AMTEC), 22 773-774 Alkali-metal titanates, 25 43 44 Alkaline autoclaving, selenium recovery via, 22 81... 

Platinized and sensitized (by ruthenium polypyridyl complexes) layered alkali-metal titanates, niobates, and titaniobates were used as photocatalysts for H2 and IJ production [91]. The use of reversed micelles as microreactors was reviewed in a feature article [92]. 

Chemical Properties. Titanium dioxide is amphoteric with very weak acidic and basic character. Accordingly, alkali-metal titanates and free titanic acids are unstable in water, forming amorphous titanium oxide hydroxides on hydrolysis. 

We discuss crystalline inorganic ion exchangers, such as [97,98,104,134-146] zeolites, hydrotal-cites, alkali metal titanates, titanium silicates, and zirconium phosphates, and also organic ionic exchangers such as the ion-exchange resins. However, details are given only in the case of the archetypal crystalline ionic exchangers, that is, aluminosilicate zeolites [97,98,104,134]. 

The book explores various examples of these important materials, including perovskites, zeolites, mesoporous molecular sieves, silica, alumina, active carbons, carbon nanotubes, titanium dioxide, magnesium oxide, clays, pillared clays, hydrotalcites, alkali metal titanates, titanium silicates, polymers, and coordination polymers. It shows how the materials are used in adsorption, ion conduction, ion exchange, gas separation, membrane reactors, catalysts, catalysts supports, sensors, pollution abatement, detergency, animal nourishment, agriculture, and sustainable energy applications. 

Barsukova M.L., Kuzneczov V.A., Malinovskay E.K. Crystalization of bivalent metals titanates under hydrothermal conditions. Kristallografiya 1972 17 1268-70. 

Figure 6.13. A selection of typical O MAS NMR spectra of metal titanates and zirconates. From Bastow et al. (1996) by permission of the copyright owner.

Q A series of alkali metal titanates are to be prepared. What preparative conditions could be suitable ... 

When TiOi is fused with metal oxides (SrO, PbO, etc.), metal titanates with intermediate band gaps can be obtained. 

Andersson, S. and Wadsley, A.D. Structures of Na2Ti60i3 and Rb2Ti60i3 and aUtani metal titanates. Acta Crystallogr. 1962,15, 194-197. 

As outlined earlier, the general strategy for the synthesis of metal titanates relies on the combination of a metal (Ba, Sr, Ni, Pb, etc.) source and a titanium precursor in a proper ratio so as to achieve the desired final composition. 

Ovromenko, N.A., Shvets, L.I., Ovcharenko, F.D. and Komilovich, B., Hydrothermal synthesis of certain alkaline earth metal titanates. Dopov. Akad. Nauk. Ukr. RSR, Ser B Geo1. Khim. Biol. Nauk., 3 242 (1978). 

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