Layered double hydroxides synthesis

Layered materials are of special interest for bio-immobilization due to the accessibility of large internal and external surface areas, potential to confine biomolecules within regularly organized interlayer spaces, and processing of colloidal dispersions for the fabrication of protein-clay films for electrochemical catalysis [83-90], These studies indicate that layered materials can serve as efficient support matrices to maintain the native structure and function of the immobilized biomolecules. Current trends in the synthesis of functional biopolymer nano composites based on layered materials (specifically layered double hydroxides) have been discussed in excellent reviews by Ruiz-Hitzky [5] and Duan [6] herein we focus specifically on the fabrication of bio-inorganic lamellar nanocomposites based on the exfoliation and ordered restacking of aminopropyl-functionalized magnesium phyllosilicate (AMP) in the presence of various biomolecules [91]. 

Abstract Layered double hydroxides (LDHs) comprise au extensive class of materials that are very easy to synthesize in the laboratory, albeit not always as pure phases. In this chapter, we review the wide variety of methods that are available for the synthesis of LDHs and focus on the way in which the physicochemical properties of the materials (such as phase piuity, crystallinity and surface area) vary with synthesis method. The flexibility of the different methods is also discussed some methods can be used to synthesize LDHs containing a wide range of constituent cations and anions, whilst others are more limited in scope. In some cases, the potential for scale-up of a method to produce larger quantities of material is also noted. 

Abstract This chapter is intended to provide a state-of-the-art review of nanocomposite materials prepared by the assembly of layered double hydroxides (LDH) and polymers, including their synthesis and characterization, and point out their potential applications. 

SYNTHESIS OF OSMATE EXCHANGED Mg-Al LAYERED DOUBLE HYDROXIDES (LDH-OSO4)... 

Synthesis and characterization of a new Sn-incorporated CoAl-layered double hydroxide (LDH) and catalytic performance of Co-spinel microcrystallites in the partial oxidation of methanol... 

It has been pointed out that these pillared intercalates are intrinsically difficult to synthesize in highly crystalline form because the layered hosts are basic, whereas most heteropolyacids are acidic and tend to decompose. Narita et al. (392) tried direct synthesis of a heteropolyanion-pillared layered double hydroxide by a coprecipitation reaction of Zn2+ and A1J+ ions in the presence of a moderately acidic lacunary Keggin anion, a-SiWn039 XRD of the product showed a basal spacing of 14.6 A, which corresponds to a gallery height of 9.9 A. The surface area was found to be 97 m2 g, which is three times that of the layered double hydroxide. 

Shi, L. Li, D., Wang, J., Li, S., Evans, D.G., and Duan, X. 2005. Synthesis, flame retardant and smoke-suppressant properties of a borate-intercalated layered double hydroxide. Clays Clay Miner., 53(3), 294-300. 

Provided in this chapter is an overview on the fundamentals of polymer nanocomposites, including structure, properties, and surface treatment of the nanoadditives, design of the modifiers, modification of the nanoadditives and structure of modified nanoadditives, synthesis and struc-ture/morphology of the polymer nanocomposites, and the effect of nanoadditives on thermal and fire performance of the matrix polymers and mechanism. Trends for the study of polymer nanocomposites are also provided. This covers all kinds of inorganic nanoadditives, but the primary focus is on clays (particularly on the silicate clays and the layered double hydroxides) and carbon nanotubes. The reader who needs to have more detailed information and/or a better picture about nanoadditives and their influence on the matrix polymers, particularly on the thermal and fire performance, may peruse some key reviews, books, and papers in this area, which are listed at the end of the chapter. 

Chibwe, M. and Jones, W. (1990). The synthesis, chemistry and catalytic applications of layered double hydroxides in Pillared Layered Solids (I. Y. Mitchell, Ed.). Elsevier Applied Sciences, London. 

Chibwe, K. and Jones, W. (1989). Synthesis of polyoxometalate-pillared layered double hydroxides via calcined precursors. Chem. Mater. 1, 489. 

Crepaldi, E. L., Pava, P. C., Valim, J. B. and Jones, W. (2000). Synthesis and thermal behaviour of copper-chromium-carbonate layered double hydroxides, in preparation. 

Velu, S., Suzuki, K., Okazaki, M., Osaki, T., Tomura, S. and Ohashi, F. (1999). Synthesis of new Sn-incorporated layered double hydroxides and their thermal evolution to mixed oxides. Chem. Mater. 11, 2163. 

Narita, E., Kaviratna, P. D. and Pinnavaia, T. J. (1993). Direct synthesis of a polyoxometalate-pillared layered double hydroxide by coprecipitation. J. Chem. Soc., Chem. Commun., 60. 

Kooli, F. and Jones, W. (1995). Direct synthesis of polyoxovanadate-pillared layered double hydroxides. Inorg. Chem. 34, 6237. 

Ulibarri, M. A., Labajos, F. M., Rives, V., Trujillano, R., Kagunya, W. and Jones, W. (1994). Comparative-study of the synthesis and properties of vanadate-exchanged layered double hydroxides. Inorg. Chem. 33, 2592. 

Newman, S. P. and Jones, W. (1998). Synthesis, characterization and applications of layered double hydroxides containing organic guests. New J. Chem. 22, 105. 

Park, I. Y., Kuroda, K. and Kato, C. (1990). Direct synthesis of intercalation compounds between a layered double hydroxide and an anionic dye. J. Chem. Soc., Dalton Trans, 3071. 

Bonnet, S., Forano, C., de Roy, A. and Besse, J. P. (1996). Synthesis of hybrid organo-mineral materials anionic tetraphenylporphyrins in layered double hydroxides. Chem. Mater. 8, 1962. 

Whilton, N. T., Vickers, P. X and Mann, S. (1997). Bioinorganic clays synthesis and characterization of amino- and polyamino acid intercalated layered double hydroxides. J. Mater. Chem. 7, 1623. 

Isupov V.P., Chupakhina L.E., Mitrofanova R.P. Mechanochemical synthesis of layered double hydroxides. In Book of Abstracts. Ill Int. Conf. INCOME, Prague, 3-8 September, 2000. 

Layered double hydroxides are typically synthesized from coprecipitation of mixed metal cations by base titration either with or withont hydrothermal treatment which nsnally enhances crystalline properties." " Becanse contamination with airborne carbonate ions freqnently occurs during synthesis procedures, special caution is needed to prepare carbonate-free LDHs. On the other hand. 

Liu, Z.P., Ma, R.Z., Osada, M., lyi, N., Ebina, Y., Takada, K., and Sasaki, T. 2006. Synthesis, anion exchange, and delamination of Co-Al layered double hydroxide Assembly of the exfoliated nanosheet/polyanion composite films and magneto-optical studies. Journal of the American Chemical Society 128. 4872-4880. 

Yarger, M.S., Steinmiller. E.M.P., and Choi, K.-S. 2008. Electrochemical synthesis of Zn-Al layered double hydroxide (LDH) films. Inorganic Chemistry 47, 5859-5865. 

Anionic copper(II)phthalocyanine monosulphonate (CuPcMs) and copper(II) phthalocyanine tetrasulphonate (CuPcTs) complexes have been successfully intercalated into the intergallery of Mg-Al layered double hydroxides through direct synthesis method. XRD results indicated an inclined orientation of the anion in the interlamellar space. A better thermal stability was noticed for the macrocycle ligand upon intercalation. The visible spectra showed a hyspochromic shift upon intercalation indicating disturbance of the macrocycle ligand pltmarity. An enhanced activity for the selective oxidation of cyclohexanol to cyclohexanone was observed for the intercalated complex in comparison with neat complex. 

The layered double hydroxides have been of interest as anion exchangers, basic catalysts, and catalyst precursors. Pillared derivatives of the type discussed earlier for the clays have been synthesized by ion exchange with polyoxometallate anions but have lower thermal stability. Several authors have reported synthesis of layered double hydroxides pillared with the Vio028 ion by direct ion exchange or by techniques that involve preswelling the layer structure with an organic anion. For example, the terephthalate anion was used in the synthesis ofVio028 and Mo7 024 intercalated phases. 

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