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2008 | Buch

Materials Syntheses

A Practical Guide

herausgegeben von: Prof. Dr. Ulrich Schubert, Prof. Dr. Nicola Hüsing, Prof. Dr. Richard M. Laine

Verlag: Springer Vienna

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SUCHEN

Über dieses Buch

Materials syntheses are generally more complex than syntheses of inorganic or organic compounds, and specific characterization methods play a more important role. Materials synthesis protocols often suffer from unclarities, irreproducibility, lack in detail and lack in standards. The need to change this situation is the main motivation for this book. A number of detailed protocols has been collected, ranging from organic polymers to carbonaceous and ceramic materials, from gels to porous and layered materials and from powders and nanoparticles to films. Preparation methods include intercalation and flux methods, sol-gel processing, templating methods for porous materials, sonochemistry or spray pyrolysis.

Each contribution provides detailed and unambiguous description of the hardware, specific characteristics of the procedure, scope of applicability as well as methods that unequivocally identify and characterize the material and allow checking whether the synthesis was successful.

Inhaltsverzeichnis

Frontmatter
Controlling Size and Morphology of Zeolite L
Abstract
The synthesis of zeolite L crystals of high purity and well-defined morphology is described. Four procedures are detailed, leading to (a) large elongated cylindrical crystals, (b) medium-sized disc-shaped crystals, (c) nano-sized crystals, and (d) medium-sized cylindrical-shaped crystals.
A. Z. Ruiz, D. Brühwiler, L. -Q. Dieu, G. Calzaferri
Zeolite A and ZK-4
Abstract
The synthesis of zeolite A and ZK-4 crystals of high purity and well-defined morphology is described. Three procedures are detailed, leading to cubic crystals of zeolite A with chamfered edges (average size 3–5 µm), cubic crystals of ZK-4 with sharp edges (average size 1–2 µm), and nano-sized cubic crystals of zeolite A with slightly rounded edges (size ≤ 1 µm).
C. Leiggener, A. Currao, G. Calzaferri
Mesostructured Silica Thin Films
Abstract
Mesoporous films composed of amorphous silica with periodically arranged pores are promising materials as catalyst supports, sensors or filtration membranes. Solvent evaporation-induced self-assembly methods based on supramolecular organization of amphiphilic molecules in combination with sol-gel processing of condensable inorganic precursors result in porous thin films with a monomodal pore size distribution. These films are typically deposited by spin coating, casting or dip coating.
J. Köhler, J. Geserick, N. Hüsing
Organically Modified Monolithic Silica Aerogels
Abstract
Organically modified silica aerogels have been prepared by sol-gel processing of methanolic solutions of R’Si(OR)3 / Si(OR)4 mixtures (R = 3-methacryloxypropyl or 2-aminoethyl-3-aminopropyl groups), followed by supercritical drying with carbon dioxide. The resulting material is characterized by a very low density (0.14–0.27 g·cm−1), high porosity and surface areas from 250 to 600 m2·g−1 depending on the kind of organic moiety used. The organic groups are easily accessible for further reactions.
N. Hüsing, U. Schubert
Porous Silica Gel by Acid Leaching of Metakaolin
Abstract
Solids, mainly composed of silica gel, were prepared by acid leaching of metakaolins. The metakaolins were prepared by calcination of a natural kaolin at different temperatures (600, 700, 800 and 900°C). The metakaolins thus prepared were treated with 6 M aqueous HCl at room temperature and at 90°C, varying the duration of the treatments. All metakaolins prepared by calcination at 600, 700 or 800°C showed a very similar reactivity, while that prepared by calcination at 900°C showed lower reactivity, due to a beginning of sintering. Treatments at room temperature did not alter either the structure or the properties of the metakaolins. Treatment under reflux conditions led to the leaching of most of the octahedral Al3+ cations. Silica-based solids were thus obtained reaching, under optimal activation conditions, high BET surface areas up to 219 m2/g and total pore volumes up to 0.065 cm3 g−1. Harsher treatments conditions (for longer periods of time) resulted in a drastic amorphisation of the final products. The solids obtained are promising adsorbents or catalyst supports.
C. Belver, M. Á. Vicente
Zirconia-Pillared Clays
Abstract
Zirconia pillared clays were prepared by intercalation of natural montmorillonite and natural saponites with zirconium polyoxo cations (prepared either by partial hydrolysis of zirconyl chloride or from zirconium acetate solution), followed by calcination. The use of the Zr acetate solution is a much less aggressive method. Well-ordered layered solids were mostly obtained, while delamination and acid leaching were observed to happen, together with intercalation, in other cases. The resulting materials contain high amounts of ZrO2, and have high surface areas (∼300 m2g−1) and pore volumes (∼0.200 cm3 −1).
M. A. Vicente, A. Gil
Montmorillonites with Mixed Aluminum-Lanthanide Oxide Pillars
Abstract
Pillared montmorillonites with mixed aluminum/cerium or aluminum/lanthanum pillars were prepared. Nuclear magnetic resonance studies indicated absence of tetrahedral aluminum in the pillars. The materials have a high thermal stability, and high specific surface area and porosity, with pores at the limit between micropore and mesopore sizes. The number and strength of the acid sites in these materials is also high.
C. Pesquera, C. Blanco, F. González
Birnessite-type Manganese Oxide by Redox Precipitation
Abstract
Preparation of a birnessite-type manganese oxide, with a layered structure, by redox and hydrothermal reactions is described. A poorly crystalline birnessite is prepared by reacting an aqueous Mn(NO3)2 solution with a NaOH / H2O2 solution at room temperature. A highly crystalline birnessite is obtained by hydrothermal treatment of the poorly crystalline birnessite in a NaOH solution.
Q. Feng, Z. -H. Liu, K. Ooi
Templated Carbon from Pyrolysis of Pyrene in Pillared Clay Matrices
Abstract
Unique carbonaceous materials suitable as anodes for lithium secondary batteries have been synthesized and characterized. The synthesis is based on the use of pillared clays and various organic precursors, including pyrene. Pyrolysis was performed at 500, 700 and 1000 °C followed by inorganic matrix removal. X-ray powder diffraction data show that the carbon samples have a highly disordered structure.
G. Sandí, K. A. Carrado, R. E. Winans
Fiberous Carbon from Sepiolite Clay and Propylene
Abstract
A pure carbon-based material with applications in electrochemical processes was synthesized using sepiolite clay as a template and propylene as the organic precursor. Carbon fibers (1–1.5 µm long) were obtained whose orientation and shape resemble that of the original clay. The results indicated that there is a correlation of the reversible specific capacity obtained and the surface properties of the template sepiolite. The electrochemical performance for anode Li cells is related to the surface chemical properties rather than the BET surface area.
G. Sandí, K. A. Carrado, R. E. Winans
Aerosol Spray Synthesis of Porous Molybdenum Sulfide Powder
Abstract
Highly porous, nanostructured MoS2 spheres have been prepared by ultrasonic spray pyrolysis (USP), an aerosol synthesis technique.[1] An aqueous solution of ammonium tetrathiomolybdate, (NH4)2MoS4, and colloidal silica, SiO2, was ultrasonically nebulized using a household humidifier; the resulting aerosol droplets are heated in a furnace where solvent evaporation and precursor decomposition occurs, yielding a MoS2/SiO2 composite. Leaching of the colloidal SiO2 with hydrofluoric acid, HF, results in a porous, high surface area MoS2 network. The resulting material is a highly active hydrodesulfurization catalyst.
S. E. Skrabalak, K. Suslick
Sonochemically Prepared Molybdenum Sulfide
Abstract
A sonochemical preparation of high surface area, sub-micron molybdenum sulfide is described.[1] A slurry of elemental sulfur and molybdenum hexacarbonyl in isodurene was irradiated with high-intensity ultrasound (20 kHz, ∼ 80 W/cm2) under Ar followed by heating under vacuum to remove residual solvent and any unreacted precursor.
A. Ryder, K. Suslick
Doped Manganites
Abstract
Two doped, mixed-valent lanthanum manganese oxides, La0.5Ba0.5MnO3 and La0.5Sr0.5MnO3 were prepared using mild hydrothermal synthesis in one step at 240°C. The fine polycrystalline powders are phase-pure, and were indexed on a primitive cubic unit cell.
J. Spooren, R. I. Walton
Lithium Manganese Oxide Prepared by Flux Methods
Abstract
Plate-like crystals of spinel-type lithium manganese oxide with sizes in the micrometer range were obtained in a flux system of LiCl-Mn(NO3)2. The crystals were grown by a dissolution-recrystallization mechanism. Polyhedral crystals with sizes in the millimeter range were grown in a flux system of LiCl-Mn(NO3)2 by an evaporation-recrystallization mechanism.
W. Tang, Q. Feng, X. Yang, R. Chitrakar, K. Ooi
Nanoscale Magnesium Oxide
Abstract
Magnesium oxide (MgO) with a crystallite size of 9±1–2 nm and a surface area of 65 m2g−1 was synthesized by precipitation of magnesium oxalate in the presence of tetraethylammonium hydroxide as a peptization agent, followed by calcination under controlled conditions.
F. Khairallah, A. Glisenti
Nanostructured Pt-doped Tin Oxide Films
Abstract
Nanostructured Pt-doped SnO2 thin films are obtained by a sol-gel route using tetra(tert-butoxy)tin(IV) and bis(acetylacetonato)platinum(II) as precursors. Acetylacetone was added as a chelating agent to control the hydrolysis and condensation of tin alkoxide and, consequently, the gelation rate. This procedure allows obtaining a sol phase viscosity suitable for the spin-coating process.
R. Scotti, C. Canevali, M. Mattoni, F. Morazzoni, L. Armelao, D. Barreca
Organically Functionalized Silica Nanoparticles
Abstract
Dense silica nanoparticles are prepared by hydrolysis and condensation of tetraethoxysilane in methanol (Stöber method). The thus prepared colloids are surface-functionalized by reaction with various functionalized alkoxysilanes.
G. Kickelbick, D. Holzinger, S. Ivanovici
Copper Nanoparticles in Silica
Abstract
Copper nanoparticles in a silica matrix are prepared by a three-step procedure. In the first step a copper salt is reacted with an alkoxysilane of the type (RO)3Si(CH2)nA, where A is a coordinating organic group. The obtained metal complexes {[(RO)3Si(CH2)nA]xCu]2+ are used as precursors for sol-gel processing, with Si(OR)4 as co-reactant to adjust the metal:silica ratio. In the second step, the metal complex-containing gels are calcined in air at high temperatures, and metal oxide nanoparticles in a silica matrix are formed. Finally, the metal oxide nanoparticles are reduced to metal nanoparticles.
U. Schubert, C. Lembacher, G. Trimmel
Copper Nanocrystals
Abstract
An anhydrous route for the synthesis of amine capped copper nanoparticles (NP) has been developed using coinage metal mesityl (mesityl = 2,4,6- Me3C6H2) derivatives. Under an argon atmosphere, [Cu(μ-mesityl)]5 was dissolved in octylamine and subsequently injected into a heated hexadecylamine solution (300°C) generating oxide-free spherical copper nanoparticles of 8–9 nm in diameter.
S. D. Bunge, T. J. Boyle
Assembly of TOPO-Capped Silver Nanoparticles to Multilayered Films
Abstract
A method for transferring silver nanoparticles from aqueous solution into organic solvents such as toluene or hexane is described. The phase-transfer reagent, tri-n-octylphosphine oxide (TOPO) provides a capping shell around Ag particles that allows concentrating the nanoparticle dispersion in toluene, which is a prerequisite for successful 3D self-assembly. The dispersed particles in toluene are stable for at least six months. Self-assembly of highly concentrated TOPO-capped Ag particle sols results in multilayered mirror-like films on glass substrates.
Z. V. Saponjic, T. Rajh, N. M. Dimitrijevic
Colloidal Dispersion of Gold Nanoparticles
Abstract
Stable sols of gold nanoparticles with an average diameter of about 13 nm were prepared from hydrogen tetrachloroaurate (prepared from bulk metallic gold) and trisodium citrate dihydrate. The organic salt acts as reducing as well as stabilizing agent for the gold nanoparticles, having an average diameter of 13±4 nm. The deep purple colloidal suspension is stable for several weeks. UV-Vis absorption spectra shows the typical surface plasmon resonance band of nanosized gold with an absorption maximum at 521.5 ± 0.5 nm.
S. Gross
One-dimensional Nanorods and Nanowires
Abstract
Gold nanorods and nanowires were fabricated by controlling the volume of growth solution. Shape evolutions ranging from rice-like nanoparticles to 1-D rods were observed. The addition of growth solution can control the length of nanorods to 2 µm, and nanorods with aspect ratios of up to ∼70 can be obtained.
Hao Ming Chen, Ru-Shi Liu
Monolithic Tin-doped Silica Glass
Abstract
Monolithic and transparent Sn-doped SiO2 glasses, where Sn atoms replaced Si centers in the SiO2 network, were prepared by a new sol-gel route by using tetraethoxysilane (TEOS) and dibutyltindiacetate (DBTDA) as precursors. The maximum amount of Sn doping was 1.40 wt % SnO2/(SnO2+SiO2) (corresponding to 0.55 mol %). At higher tin content (≥ 1.60 wt %, corresponding to 0.64 mol %) crystalline nanosized particles of SnO2 (6–10 nm) segregated in silica matrix.
N. Chiodini, F. Morazzoni, R. Scotti
Octaphenyloctasilsesquioxane and Polyphenylsilsesquioxane for Nanocomposites
Abstract
A simple two step reaction was developed to prepare octaphenyloctasilsesquioxane ([PhSiO1.5]8, OPS) in high yield from phenyltrichlorosilane (PhSiCl3). Octaphenyloctasilsesquioxane is easily modified by a wide number of electrophilic reactions to provide octa and hexadeca functionalized compounds that can be used as three-dimensional building blocks for nanometer-by-nanometer construction of composite materials. In this study, PhSiCl3 was reacted with ethanol under reflux to produce two products, one is the liquid phenyltriethoxysilane [PhSi(OEt)3, PTES], the other is an uncharacterized polymeric material likely, EtO[PhSiO(OEt)]n. OPS was synthesized from both products. PTES gave primarily one crystal form of OPS. However, this material was contaminated by another compound not be easily separated because of the insolubility of OPS. In contrast, the polymeric version of PTES, when dissolved and reacted under identical conditions, gave a second phase of OPS analytically pure as formed. This same polymeric starting material, when reacted with catalytic amounts of KOH in ethanol, provided high molecular weight polyphenylsilsesquioxane (PPS) with only small amounts of OPS.
S. -G. Kim, S. Sulaiman, D. Fargier, R. M. Laine
Polysilsesquicarbodiimide Xerogels
Abstract
Polysilsesquicarbodiimide xerogels have been prepared by sol-gel processing of chlorosilanes, R x SiCl4−x (R = H, alkyl or aryl; x = 0, 1, or, 2) and bis(trimethylsilyl)carbodiimide. The reactions can be performed with or without organic solvents and are catalyzed by pyridine. Depending on the solvents and the applied experimental conditions, the product is obtained as a fine powder or as a gel. Heat treatment transforms the xerogels to ceramic materials in the ternary Si/C/N system.
S. Nahar-Borchert, A. O. Gabriel, R. Riedel
Polyaniline — A Conducting Polymer
Abstract
Polyaniline, a conducting polymer, is prepared by the oxidation of aniline hydrochloride with ammonium peroxodisulfate in aqueous medium. The polymer is obtained in nearly quantitative yield; its conductivity at 20°C is 4.4 Scm−1. Protonated polyaniline is converted to non-conducting polyaniline base by treatment with ammonium hydroxide solution.
J. Stejskal, I. Sapurina
Allyl- and Hydroxytelechelic Poly(isobutylenes)
Abstract
Telechelic polyisobutylenes with low polydispersities and defined chain lengths can be obtained by quasiliving cationic polymerization of isobutylene in high yields up to molecular weights of 105 g mol−1. Ally- and hydroxyl-endgroups can be introduced quantitatively.
W. H. Binder, R. Zirbs
Symmetrically and Unsymmetrically Substituted Phthalocyanines
Abstract
A symmetrically and an unsymmetrically substituted phthalocyanine was synthesized by template reaction between the correspondent dinitriles and the metal salts. Considerations were made regarding the mechanistic process, as well as product distribution in the case of the unsymmetrically substituted phthalocyanine, which was synthesized by statistical condensation. These types of phthalocyanines are very important materials for nonlinear optic applications and for further functionalization to produce e.g. phthalocyanine polymers.
M. J. Ferreira Calvete, M. Hanack
Backmatter
Metadaten
Titel
Materials Syntheses
herausgegeben von
Prof. Dr. Ulrich Schubert
Prof. Dr. Nicola Hüsing
Prof. Dr. Richard M. Laine
Copyright-Jahr
2008
Verlag
Springer Vienna
Electronic ISBN
978-3-211-75125-1
Print ISBN
978-3-211-75124-4
DOI
https://doi.org/10.1007/978-3-211-75125-1

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