Titanates layered oxides

Unal U, Matsumoto Y, Tanaka N, Kimura Y, Tamoto N (2003) Electrostatic self-assembly deposition of Titanate(IV) layered oxides intercalated with transition metal complexes and their electrochemical properties. J Phys Chem B 107 12680-12689... 

Group (IV) metal phosphates and phosphonates, transition metal oxides (titanates, silicates, niobates, etc.), layered oxides, and double hydroxides (aluminum, magnesium, iron, etc.) are some of the inorganic compounds used as layered host ma-... 

Inorganic layered oxides have attracted considerable attention due to their unique structural properties and applications, such as in intercalation reactions, ionic exchange processes, photochemical and semiconductor properties, and catalytic applications. In this chapter, titanates, niobates, tungstates, molybdates, and molybdenum oxide will be considered as specific examples. However, it is necessary to say that many other specific lamellar oxides are investigated, such as V2O5. 

Rodionov, I.A., Silyukov, O.I., and Zvereva, A. (2012) Study of photocatalytic activity of layered oxides NaNdTi04, LiNdTiP4, and HNdTi04 titanates. Russ. J. Gen. Chem., 82 (4), 635-638. 

In principle, all lamellar minerals may be used as barrier pigments, e.g., micaceous iron oxide [5.167]-[5.169], layer silicates (mica), linear polymeric silicates (wollas-tonite), and talc [5.170], However, untreated mica and talc are not very suitable because they are highly permeable to water [5.57]. The surface can be modified with, for example, silanes or titanates, to reduce water permeability and improve adhesion... 

The Kagome lattice structure clearly explains the non-symmetric nature of the band structure of the C0O2 layer. When the effect of the Kagome lattice becomes dominant, the bottom band, i.e., the flat band as shown in Fig, 3(a) will play a crucial role on the electronic state. Mielke [32] has shown that the flat band with the Coulomb interaction has the ferromagnetic ground state at around half filling. A prospective system for the ferromagnet will be dl transition metal oxides, i.e., the layered titanates with iso-structure of the cobalt oxides. 

Examples of known phosphazene polymer blends are those in which phosphazenes with methylamino, trifluoroethoxy, phenoxy, or oligo-ethyleneoxy side groups form blends with poly(vinyl chloride), polystyrene, poly(methyl methacrylate), or polyethylene oxide).97 100 IPNs have been produced from [NP(OCH2CH2OCH2CH2OCH3)2] (MEEP) and poly(methyl methacrylate).101-103 In addition, a special type of IPN has been reported in which a water-soluble polyphosphazene such as MEEP forms an IPN with a silicate or titanate network generated by hydrolysis of tetraethoxysilane or tetraalkoxytitanane.104 These materials are polyphosphazene/ceramic composites, which have been described as suitable materials for the preparation of antistatic layers in the manufacture of photographic film. 

High-quality, pore-free microstructures of PZ - PT piezoceramic, (b) and (c), are essential for reliable, high-performance applications, e.g. composites and arrays where very small elements are cut from larger pieces (e.g. see Fig. 6.36) (d) the layer-structured bismuth titanate ferroelectric (Bi4Ti3012) Tc 650°C the crystal structure consists of perovskite layers separated by bismuth oxide layers) is exploited in high-temperature applications, including accelerometers and flow-meters (reproduced with permission of Ferroperm Piezoceramics A/S, Denmark). 

The 0-d nanoparticles can be nano-metal oxides (such as silica,1 titania,2 alumina3), nano-metal carbide,4 and polyhedral oligomeric silsesquioxanes (POSS),5 to name just a few the 1-d nanofibers can be carbon nanofiber,6 and carbon nanotubes (CNT),7 which could be single-wall CNTs (SWCNT) or multiwall CNTs (MWCNT) etc. the 2-d nano-layers include, but are not limited to, layered silicates,8 layered double hydroxides (LDH),9 layered zirconium phosphate,10 and layered titanates,11 etc. 3-d nano-networks are rarely used and thus examples are not provided here. 

The results discussed above show that a high dispersion of vanadium oxide in the fresh catalyst is not a guarantee for the stability of the layer. The high dispersion must be retained under reaction conditions and the support material must not only stabilize the vanadium oxide layer in its oxidized form but also in the reduced state. Regarding this fact, titan a (anatase) seems to be one of the most promising support materials. 

Titanizing [From the Greek, Titan, meaning a person of superhuman strength often incorrectly assumed to be derived from the name of the element titanium] A process for hardening the surfaces of glass vessels by coating them with a layer of titanium dioxide or tin dioxide. The oxides are... 

Change in the selectivity patterns of transition metal ion/H+ systems has been encountered with the amorphous and anatase types of hydrous titanium oxides with different crystallinities [24]. Potassium titanate, KjO nXi02 (n = 2-4), in particular, exhibits a layered structure. Fibrous titanic acid, H2Ti409 nHjO, is obtained by acid treatment of fibrous K2Ti409 nH20 and shows higher selectivity for K, Rb and Cs than the amorphous titanic acid [206]. 

Titanates and titanoniobates of the general formula A2-vTi vNbv02 +1 (A = alkali metal) crystallize in layered structures possessing [Ti , vNbv02 +i sheets stacked with interlayer A ions [1, 2]. The sheets may be obtained from edge-connected layers of double-ReOr units by shearing every n-octahedron perpendicular to the sheets. Idealized structures of some of these oxides are shown in Figure 1. Several oxides in this family are known to exhibit interlayer chemistry... 

Perovskite-related Oxides.—The perovskite-related oxides have been studied extensively in recent years because of the large variety of device applications for which these materials are suited. The interaction between structure, properties, and stoicheiometry is significant at all levels, but here we will discuss only the narrow areas where intergrowth is a dominant structural feature. We will not, therefore, consider solid solutions typified by the Pb(Zr Tii )03 ferroelectrics, and neither will we discuss the structurally complex but stoicheiometric phases related to hexagonal BaTiOj, which includes BaNiOj, which has a simple two-layer repeat in the c-direc-tion, the nine layer BaRuOj, the twelve layer Ba4Re2CoOj2, and the twenty-four layer Sr5Re20ig phase. The crystal chemistry of these phases is treated in detail by Muller and Roy. The materials we shall discuss are the two series of phases A B 0 +2 and A + B 02n+, and the bismuth titanates. Some of the anion deficient perovskites, ABO -x, will be considered in Section 5. 

The Bismuth Titanates. This family of materials was one of the first complex perovskite groups to be discovered the early studies being made by Aurivillius and reported in 1949. The structures are well known and described in standard texts such as Wells. The general architectural principle of these materials is a repetition of perovskite layers n octahedra thick cut parallel to (110) as in the Sr +iTi 03 +i oxides described above. Instead of being held together by a sequence of SrO layers, the perovskite layers in the bismuth titanates are joined by (Bi202) layers. The perovskite slabs have an overall formula where /I is a large cation that can readily... 

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