Oxygen titanium oxide

Titanium oxide dichloride [13780-39-8] TiOCl2, is a yellow hygroscopic soHd that may be prepared by bubbling ozone or chlorine monoxide through titanium tetrachloride. It is insoluble in nonpolar solvents but forms a large number of adducts with oxygen donors, eg, ether. It decomposes to titanium tetrachloride and titanium dioxide at temperatures of ca 180°C (136). 

In iadustrial production of titanium carbide, pure (99.8%, with minor impurities of Si, Fe, S, P, and alkahes) titanium oxide [13463-67-7] Ti02, iu the dry or wet state is mixed iu 68.5 31.5 ratio with carbon black or finely milled low ash graphite. The dry mixture is pressed iato blocks that are heated iu a horizontal or vertical carbon-tube furnace at 1900—2300°C hydrogen that is free of oxygen and nitrogen serves as protective gas. In the vertical push-type furnaces, the Hberated CO itself provides protection. 

Figure 1 shows AES data for the oxidized titanium surface before and after deposition of 30 X of platinum with the substrate held at 130 K. The platinum thickness was calculated from the attenuation of the oxygen AES signal assuming layered growth of the metal. From the spectra It Is clear that the platinum was sufficient to completely attenuate the underlaying features of the titanium oxide. 

The above results on detection of trace concentrations of oxygen by sine oxide films (and titanium oxide films, to a lesser degree), as well as the results on detection of alkyl radicals, which are acceptors of semiconductor electrons, show that the behaviour and electric properties of... 

Heat-flow calorimetry may be used also to detect the surface modifications which occur very frequently when a freshly prepared catalyst contacts the reaction mixture. Reduction of titanium oxide at 450°C by carbon monoxide for 15 hr, for instance, enhances the catalytic activity of the solid for the oxidation of carbon monoxide at 450°C (84) and creates very active sites with respect to oxygen. The differential heats of adsorption of oxygen at 450°C on the surface of reduced titanium dioxide (anatase) have been measured with a high-temperature Calvet calorimeter (67). The results of two separate experiments on different samples are presented on Fig. 34 in order to show the reproducibility of the determination of differential heats and of the sample preparation. 

Fig. 34. Differential heats of adsorption of oxygen at 450°C on the surface of samples of titanium oxide (anatase) which have been previously reduced by carbon monoxide (pco = 70 Torr) at 450°C for 15 hr 67).

Fig. 10-16. Polarization curves for anodic oxygen and cathodic hydrogen redox reactions on an n-type semiconductor electrode of titanium oxide in the dark and in a photoex-cited state i = anodic current in the dark (zero) = anodic current...

The same sequence using the three oxidations states of titanium occurs with oxygen to form II, III, and rV titanium oxides. 

Powell R. and Powell M. (1977b). Geothermometry and oxygen barometry using iron-titanium oxides A reappraisal. Min. Mag, 41 257-263. 

The kinetics that control the small droplet reaction are characterised by the dissolution of titanium oxide which, in turn, exposes further, unoxidised metal. Interestingly, this process appears to be independent of the type of oxidant, whether it be potassium perchlorate, potassium nitrate or atmospheric oxygen. 

Suda Y, Kawasaki H, Ueda T, Ohshima T (2005) Preparation of nitrogen-doped titanium oxide thin film using a PLD method as parameters of target material and nitrogen concentration ratio in nitrogen/oxygen gas mixture. Thin Solid Films 475 337-341... 

One other type of oxygen sensor has received considerable attention as an alternative to the galvanic type of sensor. This is the resistive type of sensor which uses a metal oxide whose resistance is dependent on the oxygen partial pressure (6). While a number of different oxides have been used, titanium oxide appears to have the best combination of properties for automotive applications (y. 

Hydrogen peroxide and alkyl hydroperoxides are important oxidants in organic synthesis, but they usually need to be activated by catalysts such as tungsten, molybdenum, and titanium oxides. Heteropoly compounds are good catalysts for oxygenation of olefins or paraffins and oxidative cleavage of vic-diols. 

Titanium silicates are catalysts for various oxidation reactions. Most of those investigated have been carried out with H202 and hydroperoxides as the oxidants, and a few have been investigated with ozone and oxygen as oxidants. 

An attempt was made to reveal the mechanism for the formation of free radicals upon irradiation of titanium dioxide in the presence of benzene and toluene. Careful examination of the effects of oxygen and water showed that the presence of oxygen is essential for the reaction, and that under oxygen the oxidation of water contributes to the aromatic hydroxylation and the oxidation of toluene as a substrate leads to oxidation of its side chain (56). 

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