Intercalation titanates

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... 

In characterizing layered silicate, including layered titanate (HTO), the surface charge density is particularly important because it determines the interlayer structure of the intercalants as well as the cation exchange capacity (CEC). Lagaly proposed a method of calculation consisting of total elemental analysis and the dimensions of the unit cell [15] ... 

Fig. 9.3 Illustration of a model of interlayer structure of intercalant N-(cocoalkyl)-N,N-[bis (2-hydroxyethyl)]-N-methyl ammonium cation (qCi4(OH)) in the gallery space of layered titanate (HTO). The average distance between exchange sites is 0.888 nm, calculated from the surface charge density of 1.26e /nm2. For qCi4(OH), the obtained molecular length,...

Finally, NMR has also be used to study other spinels materials that do not contain manganese. For example, the intercalation/deintercalation of lithium titanate spinels such as Li4/3+Ji5/304 and Lii.i-Tii.904+a have been investigated. These materials may be used as anode materials in combination with cathodes operating at 4 V (vs Li) to produce cells with potentials of ca. 2.5 V. These materials are either diamagnetic or metallic, and unlike the mangan-ates, only very small differences in shifts are seen for Li in the different sites of the spinel structure. Nonetheless, these shift differences are enough to allow the concentrations of the different sites to be quantified and monitored following insertion of Li or as a function sample preparation method. ... 

Figure 56 (a-d) Schematic interlayer structure of the intercalation compounds of the layered niobates and titanates with Ru(bpy)3+ ions. See text for more details. (From Ref. 109b. Copyright 1995 The American Chemical Society.)... 

The proton exchanged form of the titanates and titanium niobates are Bronsted acids and intercalate bases in the same... 

Layered compounds provide unique character for electron-transfer processes owing to their low dimensionality. Especially layered materials with ion-exchange and/or intercalation capabilities show behavior that is not seen in so-called bulk-type materials. Layered materials, which have been often used in studies of photoelectron transfer as well as photocatalysis, may be classified into two groups compounds in which the host layers work as an active component for the photoexcitation and electron-transfer reactions, and materials in which the layers are inert for electron-transfer processes. Examples of the former are layered titanates and niobates and of the latter are clays. In the latter case, photoactive materials are intercalated in the interlayer spaces. Recently, the exfoliation of various layered compounds has become possible and artificial assemblies consisting of these exfoliated sheets have been formed. Electron transfer in such assemblies is also an attractive subject in this field. 

Nano-composite photocatalysts, CuOx-TiOa, were synthesized from Cu(OAc)2-intercalated fibrous layered titanates by thermal decomposition in different atmospheres (N2, air, and H2). The structural characterization using XRD, UV-vis, XPS, and SEM implied that the composite of partially reduced CuOx and anatase-t)q3e Ti02 in a waffle-like texture would be a reason for the excellent photocatalytic activity for H2 production from CH3OH/H2O mbttures. 

Table 4 shows the photocatalytic activity of CuOx supported on the pristine samples of layered titanates. The loading (26 wt% Cu) corresponds to the Cu/Ti ratio (0.33) for the composite prepared by the intercalation process. The two pristine layered titanates showed very low activity without loading CuOx. In contrast, the activity of the CuOx-loaded samples was quite different the protonated phase produced ca. 18-times higher rate of Ha evolution. Copper oxides in these materials were deposited only on the surface of the fibrous crystals. However, the protonated phase was decomposed to produce anatase-type TiOa as in the case of the intercalated composite (Fig. 5). This result also supports that the formation of anatase is essential for the photocatalytic activity. 

A large number of inorganic layer crystals such as micas, sodium silicates, niobate, uranate, vanadate, titanate, zirconium phosphate, graphitic acids, crystalline silicic acids, vanadium oxyhydrate, calcium phosphoric acid esters, and titanium disulfide develop alkyl crystals between their rigid crystal layers by ion exchange with, for example, alkyl ammonium salts and by intercalation inorganic... 

Weng et al. [113] studied the effect of tetramethylammonium cations (TMA"") on HO2 crystal morphology under hydrothermal conditions. The as-synthesized samples were characterized by XRD, TEM and SEM methods (see Table 2). The observed morphologies include besom-like particle, nanosheet and nanotubes. The mechanism to accelerate the formation of nanotube in the base of NaOH/TMAOH mixture is illustrated in Eigure 7. Bulk HO2 is first exfoliated to be layered protonic titanate by the mineralization effect of Na". In the presence of TMA"" cations, the separation of layered protonic titanate is accelerated by intercalating TMA"" cations in layered titanate. As a result of the presence of more layered titanate in the hydrothermal solution, nanotubes are formed ahead of schedule by curliness of layered titanate. Thus, the mechanism through which TMA cations affect crystal growth in the conditions of this study is different. 

J. Li, Z. Tang, Z. Zhang, Layered hydrogen Titanate nanowires with novel lithium intercalation properties . Chemistry of Materials, 17(23), 5848-5855, (2005). 

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. 

Figure 6.13 FTIR of(polyaniline)o JHT1O2. (Reprinted with permission from Synthetic Metals, An intercalated polyaniline-titanate nanomaterial by 5. F. Scully and R. Bissessur, 159, 7-8 637-641. Copyright (2009) Elsevier Ltd)...

Two-dimensional layers or sheets of metal oxides are of importance by virtue of their properties of practical importance. In this context, the early report of the preparation of single layers of titanates by delamination of layered titanates by Sasaki and co-workers [276] deserves special mention. An important strategy employed for delamination or exfoliation is to use intercalants such as tetrabutylammonium ion or... 

In order to avoid the problems associated with the instability of the n-doping process of the polymer, it has been proposed to replace the n-doped polymer at the negative electrode with a carbon electrode to form the so-called hybrid capacitor [22, 33, 40]. Such hybrid capacitors with a p-doped polythiophene derivative as the positive electrode and activated carbon as the negative electrode were found to outperform double-layer carbon capacitors in terms of specific power while maintaining good performance cyclability over 10000 cycles [40]. Another asymmetric hybrid capacitor has been built using a lithium titanate (Li4Ti50i2) intercalation anode, instead of a carbon electrode and PFPT electrode [35]. 

Layered crystalline titanates (CT) [Anthony and Dosch, U.S. Patent 5 177 045 (1993)] are pillared with tetraethyl orthosilicate, 3-aminopropyltrimethoxysilane, and aluminum(III) acetylacetonate to prepare porous and high surface area supports for sulfided NiMo catalyst. Tetraethyl orthosilicate or aluminum(III) acetylacetonate intercalated CT are prepared by stepwise intercalation. First, the basal distance is increased by n-alkylammonium ions prior to intercalation with inorganic compounds. However, an aqueous solution of 3-aminopropyltrimethoxysilane can directly pillar CT without first swelling the titanate with n-alkylamine. The catalytic activities for hydrogenation of pyrene of sulfided NiMo supported silica or alumina pillared CT are higher than those of commercial catalysts (Shell324 and AmocatlC). The silicon and aluminum contents of the pillared CT, used as supports, have considerable effects on the catalytic activities and physical properties of the supports. 

A silica-pillared layered titanate was prepared by reacting HjTi O, with pure NH2 (CHj) jSi (OC Hj)3 (abbreviated hereafter as APS), washing the precipitate with water, which leads to the hydrolysis and polymerization of the intercalated APS with the formation of APS oligomers, and calcinating the product in air at 500 C to remove the interlayered organics. The silica-pillared layered titanate thus obtained has an interlayer distance of 14.and a specific surface area of 45.9m /g. 

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