Oxide substrates perovskite

Franco T, HoshiarDin Z, Szabo P, Lang M, and Schiller G. Plasma sprayed diffusion barrier layers based on doped perovskite-type LaCr03 at substrate-anode interface in solid oxide fuel cells. J. Fuel Cell Sci. Technol. 2007 4 406-412. 

Thin films, to attain enough sensitivity and response time, of oxide materials normally deposited on a substrate are typically used as gas sensors, owing to their surface conductivity variation following surface chemisorption [183,184], Surface adsorption on a Sn02 film deposited on alumina produces a sensitive and selective H2S gas sensor [185]. In addition, a number of perovskite-type compounds are being used as gas sensor materials because of their thermal and chemical stabilities. BaTi03, for example, is used as sensor for C02 [183],... 

Studies of perovskite and other oxide electrocatalysts continue to be of great interest [115-118]. The high activities of perovskite catalysts for the oxidation of organic substances [119,120] has stimulated related electrocatalytic studies [121-123]. Perovskites are also convenient inactive substrates for electroanalytical purposes [124]. These investigations are intrinsically related to the electrochemistry of HTSC and serve therefore to extend the circle of well-characterized electrode materials. 

The choice of conducting substrate becomes more difficult when postdeposition high-temperature treatments are necessary. This is often the case for complex oxides, such as perovskites or oxynitrides [9], which may require firing at temperatures above 600°C in order to obtain the desired crystalline phase. This prohibits the use of float glass, which softens above 550°C. Certain types of borosilicate glass can be used up to 650 C, while fused silica or sapphire can withstand continuous exposure to temperatures up to 950°C. Unfortunately, the conductivity of ITO films quickly decreases above 350°C. FTO and ITO/FTO coatings are stable up to 600-700 C [2,10], and may still have acceptable conductivities at higher temperatures provided... 

The three types of solids, metals, covalent semiconductors or insulators, and ionic compounds (including oxides) have characteristic surface reactions. In organic catalysis only metals and ionics are considered (Table 6.5), while in CVD all three types of solid surfaces are of interest. Metals absorb hydrogen and nitrogen dissociatively while ionic substrates have redox reactions or acid/base reactions with molecules. Oxidation of gases is often catalyzed by the surface of metal oxides. So is deposition of oxides by oxidation and hydrolysis of metal-containing precursors. When mixed oxides (e.g., perovskites) are deposited care must be taken to ensure a sufficient availability of the separate components. 

The strains induced by the substrate in the film for epitaxial growth can extend the stability limit for the layered-structure perovskite. In previous work [98], we have shown that it can be expanded up to Gd2Ti20y oxide when grown on (110)-SrTiO3 substrate. As such, the Figure 11.8 shows the XRD patterns obtained for Ln2Ti207 (Ln = Sm to Tb) in bulk and in thin films form when... 

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