Edge titanium oxides

Knapp et al. (144) show that for oxides containing 3d elements in spinel, perovskite, rocksalt, or zircon-type structures, the K-edge XANES spectra are quite independent of 3d electron occupation but instead nicely correlate with the crystal structure type. Various studies of Ti K edges of titanium oxides and other titanium compounds have been reported (40,158,172,177, 297). 

Highly dispersed titanium oxide species within AI2O3 or Si02 matrices can be prepared easily by the sol-gel method or a precipitation method (10-14, 28-30). From the X-ray diffraction (XRD) measurements, the particle sizes of the titanium oxide species in the binary oxides become smaller as the Ti content decreases. Figure 18.2 shows the XAFS spectra of Ti/Si binary oxides having different Ti contents. The Ti A-edge X-ray absorption near-edge stracture (XANES left) of the binary oxides with lower Ti content of less than 10 wt% exhibited an intense... 

Stoichiometric titanium(II) oxide and magnesium oxide have densities of 4.93 and 3.58 g cm-3, respectively. They both have the NaCl structure, with unit cells of edge 416.2 and 421.2 pm, respectively. Show that only about 84% of the lattice sites in TiO, but essentially all in MgO, are filled. 

Preparation of Thin Tilms of TiOx on Palladium Foils. Following the procedure reported by Takahashi, an isopropanol based sol of titanium tetra-isopropoxide (TnP) was prepared (10 mL of TUP in 48.4 mL of 2-propanol), to which 6.7 mL of diethanolamine was added to inhibit the formation of oxides. This mixture was stirred for two hours, at which time gel formation was initiated by the addition of 28.1 mL of a dilute water solution (1.42 mL water in 30 mL of 2-propanol). The resulting molar ratio of water to TUP was 2 1, as was recommended by Takahashi and co-workers (22). The palladium substrates were dipped vertically into this solution and then clamped on edge while draining to allow the excess to drip off and to prepare as even a coating as possible. The membranes were then air-dried in a vertical position at 100°C for one hour, followed by a post-treatment with hydrogen (see Figure 2). 

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