Showing papers in "Chemistry of Materials in 2001"
TL;DR: A critical review of adsorption methods that are currently used in the characterization of ordered organic−inorganic nanocomposite materials is presented in this paper, where the authors compare and evaluate the available methods for mesopore size analysis.
Abstract: A critical review of adsorption methods that are currently used in the characterization of ordered organic−inorganic nanocomposite materials is presented, and the adsorption methodology that is potentially useful for this characterization, but has not yet been applied, is discussed. The ordered organic−inorganic nanocomposites include surface-functionalized ordered mesoporous materials (OMMs) with siliceous frameworks (synthesized either via postsynthesis surface modification or via direct co-condensation method), periodic mesoporous organosilicas, and surfactant-containing OMMs. This review covers the methods for determination of the specific surface area and pore volume. The available methods for mesopore size analysis are critically compared and evaluated, with special emphasis on the recent developments related to the application of advanced computational methods for studying adsorption in porous media and to the direct modeling of adsorption using highly ordered surface-functionalized OMMs as model a...
2,987 citations
TL;DR: In this paper, a new application of MCM-41 mesoporous materials has been developed, where two kinds of surfactants, C16TAB and C12TAB, have been employed to get different pore sizes.
Abstract: A new application of MCM-41 mesoporous materials has been developed. Two kinds of surfactants, C16TAB and C12TAB, have been employed to get different pore sizes. The samples were disk-shaped conformed before and after charging with ibuprofen, an anti-inflammatory drug. In all the cases the weight percent ratio of drug/MCM-41 was 30%. The drug release plots show a different behavior depending on the method for charging the drug in the material but not on the employed surfactant.
1,955 citations
TL;DR: Inkjet printing has been used as a free-form fabrication method for building three-dimensional parts and is being explored as a way of printing electrical and optical devices, especially where these involve organic components.
Abstract: Inkjet printing is familiar as a method of printing text and images onto porous surfaces. In the last few years it has been used as a free-form fabrication method for building three-dimensional parts and is being explored as a way of printing electrical and optical devices, especially where these involve organic components. Inkjet printers are also being used to produce arrays of proteins and nucleic acids. The need for a versatile inkjet technology for free-forming materials and for multilayer devices raises a number of materials problems that do not apply to conventional printing of images. Higher resolutions will be needed if organic transistors are to be printed. Also, it must be possible to print pinhole-free layers to avoid shorting of devices. Multiple layers must be printed such that they mix and react to form a single material or such that they form discrete unmixed layers. Printing on dense rather than porous substrates will be the norm. This article reviews the range of materials that has been ...
1,774 citations
TL;DR: In this article, the synthesis and study of so-called "nanoparticles" with diameters in the range of 1−20 nm, has become a major interdisciplinary area of research over the past 10 years.
Abstract: The synthesis and study of so-called “nanoparticles”, particles with diameters in the range of 1−20 nm, has become a major interdisciplinary area of research over the past 10 years. Semiconductor nanoparticles promise to play a major role in several new technologies. The intense interest in this area derives from their unique chemical and electronic properties, which gives rise to their potential use in the fields of nonlinear optics, luminescence, electronics, catalysis, solar energy conversion, and optoelectronics, as well as other areas. The small dimensions of these particles result in different physical properties from those observed in the corresponding macrocrystalline, “bulk”, material. As particle sizes become smaller, the ratio of surface atoms to those in the interior increase, leading to the surface properties playing an important role in the properties of the material. Semiconductor nanoparticles also exhibit a change in their electronic properties relative to that of the bulk material; as th...
1,213 citations
TL;DR: In this paper, the core integrity of inorganic nanobuilding blocks (NBBs) is preserved and the main synthetic procedures presented in the literature are reviewed and extended to nanoparticule-based hybrid networks.
Abstract: This article describes hybrid materials and systems in which the core integrity of inorganic nanobuilding blocks (NBBs) is preserved and reviews the main synthetic procedures presented in the literature. The relation between the NBB and the resulting hybrid networks is discussed for several striking examples: silicon and tin oxo clusters, polyoxometalates, and transition metal−oxo-based clusters. This approach is extended to nanoparticule-based hybrids. The chemical strategies offered by the coupling of soft chemistry processes and this approach based on functional NBBs allows, through an intelligent and tuned coding, to develop a new vectorial chemistry that is able to direct the assembly of a large variety of structurally well-defined clusters or nanoparticles into complex architectures.
1,124 citations
TL;DR: The thermal stability of organically modified layered silicate (OLS) plays a key role in the synthesis and processing of polymer-layered silicate nanocomposites as discussed by the authors.
Abstract: The thermal stability of organically modified layered silicate (OLS) plays a key role in the synthesis and processing of polymer-layered silicate (PLS) nanocomposites. The nonoxidative thermal degradation of montmorillonite and alkyl quaternary ammonium-modified montmorillonite were examined using conventional and high-resolution TGA combined with Fourier transform infrared spectroscopy and mass spectrometry (TG−FTIR−MS) and pyrolysis/GC−MS. The onset temperature of decomposition of these OLSs was approximately 155 °C via TGA and 180 °C via TGA−MS, where TGA−MS enables the differentiation of water desorbtion from true organic decomposition. Analysis of products (GC−MS) indicates that the initial degradation of the surfactant in the OLS follows a Hoffmann elimination reaction and that the architecture (trimethyl or dimethyl), chain length, surfactant mixture, exchanged ratio, or preconditioning (washing) does not alter the initial onset temperatures. Catalytic sites on the aluminosilicate layer reduce ther...
961 citations
TL;DR: In this article, the photocatalytic activity of tetragonal BiVO4 for O2 evolution from an aqueous AgNO3 solution under visible light irradiation was negligible.
Abstract: BiVO4 powder with scheelite structure was obtained by hydrolyzing a nitric acid solution of Bi(NO3)3 and Na3VO4 with bases (Na2CO3 and NaHCO3) at room temperature. Tetragonal BiVO4 of a high-temperature form was obtained after 4.5 h of preparation time while monoclinic BiVO4 was done after 46 h. Although the structure and the band gap of tetragonal BiVO4 with scheelite structure were similar to those of monoclinic BiVO4, the photocatalytic activity of the tetragonal BiVO4 for O2 evolution from an aqueous AgNO3 solution under visible light irradiation was negligible. In contrast, the monoclinic BiVO4 showed high photocatalytic activity. Distortion of a Bi−O polyhedron by a 6s2 lone pair of Bi3+ plays an important role for high photocatalytic activity of the monoclinic BiVO4 under visible light irradiation.
947 citations
TL;DR: The ability to generate homogeneous particulate thin films of highly oriented and highly porous microparticles of a post transition metal oxide by a template-free, aqueous low-temperature coating process is demonstrated in this paper.
Abstract: The ability to generate homogeneous particulate thin films of highly oriented and highly porous microparticles of a post transition metal oxide onto polycrystalline and single-crystalline substrates, at low cost, by a template-free, aqueous low-temperature coating process is demonstrated by the fabrication of a large three-dimensional array of perpendicularly oriented hexagonal microtubes of crystalline zincite ZnO from an aqueous solution of zinc nitrate and methenamine.
896 citations
TL;DR: The synthetic routes and materials properties of polypropylene/montmorillonite nanocomposites are reviewed in this article, where the resulting polymer/inorganic structures are characterized by a coexistence of intercalated and exfoliated montmorillonites layers.
Abstract: The synthetic routes and materials properties of polypropylene/montmorillonite nanocomposites are reviewed. The nanocomposite formation is achieved in two ways: either by using functionalized polypropylenes and common organo-montmorillonites, or by using neat/unmodified polypropylene and a semi-fluorinated organic modification for the silicates. All the hybrids can be formed by solventless melt-intercalation or extrusion, and the resulting polymer/inorganic structures are characterized by a coexistence of intercalated and exfoliated montmorillonite layers. Small additionstypically less than 6 wt %of these nanoscale inorganic fillers promote concurrently several of the polypropylene materials properties, including improved tensile characteristics, higher heat deflection temperature, retained optical clarity, high barrier properties, better scratch resistance, and increased flame retardancy.
871 citations
TL;DR: The area of periodic mesoporous materials prepared by cooperative assembly in the presence of amphiphile molecules underwent dramatic growth as discussed by the authors, and many types may be regrouped in the future.
Abstract: The area of periodic mesoporous materials prepared by cooperative assembly in the presence of amphiphile molecules underwent dramatic growth. Among the silica-based materials, many types may be reg...
810 citations
TL;DR: In this paper, the synthesis and properties of non-siliceous ordered mesoporous materials, covering oxidic, non-oxidic, metallic, and pure carbon frameworks, are addressed.
Abstract: Siliceous ordered mesoporous materials are well-investigated and -covered by several excellent reviews. Less work has been directed to non-siliceous materials, although these could have more wide-ranging applications. This review will address the synthesis and properties of non-siliceous ordered mesoporous materials, covering oxidic, non-oxidic, metallic, and pure carbon frameworks. Organometallic frameworks, which are typically not synthesized in the presence of surfactants, are beyond the scope of this paper.
TL;DR: In this paper, the synthesis and characterization of nanocomposite materials built from the assembly of organic polymers and two-dimensional host materials, particularly those composed of layered double hydroxide (LDH) inorganic frameworks, is described.
Abstract: The present paper describes the synthesis and characterization of nanocomposite materials built from the assembly of organic polymers and two-dimensional host materials, particularly reviewing those composed of layered double hydroxide (LDH) inorganic frameworks. When the meaning commonly adopted for nanocomposites is narrowed, the system is constituted of sheets lying on top of each other in which covalent forces maintain the chemical integrity and define an interlamellar gap filled up with the polymer guest. The situation is different from an inorganic filler dispersed into a polymeric matrix. The incorporation of polymer between the galleries proceeds via different pathways such as coprecipitation, exchange, in situ polymerization, surfactant-mediated incorporation, hydrothermal treatment, reconstruction, or restacking. The latter method, recently effective via the exfoliation of the LDH layers, appears to be more favorable, in terms of crystallinity, to capture monomer entities than the whole polymer....
TL;DR: In this article, the role of electron lone pairs in stabilizing the highly distorted perovskite structure is examined using real-space visualization of the electronic structure, drawing comparisons with the electronic structures of hypothetical cubic BiMnO3 and with the prototypical perovsite manganite, LaMn O3.
Abstract: Results of first-principles electronic structure calculations on the low-temperature monoclinic phase of the ferromagnetic perovskite BiMnO3 [Atou et al. J. Solid State Chem. 1999, 145, 639] are presented. In agreement with experiments, the calculations obtain an insulating ferromagnetic ground state for this material. The role of Bi 6s “lone pairs” in stabilizing the highly distorted perovskite structure is examined using real-space visualization of the electronic structure. Comparisons are drawn with the electronic structures of hypothetical cubic BiMnO3 and with the electronic structure of the prototypical perovskite manganite, LaMnO3. The exploitation of s electron lone pairs in the design of new ferroic materials is suggested.
TL;DR: The preparation of hybrid organic/inorganic nanocomposites comprised of well-defined polymers was reviewed in this article, in particular, synthetic methods using controlled/living radical polymerization techniq...
Abstract: The preparation of hybrid organic/inorganic nanocomposites comprised of well-defined polymers was reviewed. In particular, synthetic methods using controlled/“living” radical polymerization techniq...
TL;DR: In this paper, the thermal reaction of single-wall carbon nanotubes with in situ generated aryl diazonium compounds is described and compared to a previously reported, electrochemically induced reaction with preformed arylsdioxonium salts.
Abstract: The thermal reaction of single-wall carbon nanotubes with in situ generated aryl diazonium compounds is described and is compared to a previously reported, electrochemically induced reaction with preformed aryl diazonium salts.
TL;DR: In this paper, the authors examined the seed-mediated growth of gold nanoparticles by transmission electron microscopy and electronic absorption spectroscopy and found that changing the seed concentration does affect the size of the product nanoparticles, but the method of reagent addition drastically affects the outcome even more.
Abstract: Central to the concept of seed-mediated growth of nanoparticles is that small nanoparticle seeds serve as nucleation centers to grow nanoparticles to a desired size. We have examined this common assumption in a model system, the wet chemical synthesis of gold nanoparticles via reduction of a gold salt, by transmission electron microscopy and electronic absorption spectroscopy. We find that changing the seed concentration does affect the size of the product nanoparticles, but the method of reagent addition drastically affects the outcome even more. For fast addition of reducing agent, the presence of seeds appears to promote the formation of more seeds instead of growth. The observed nucleations are drastically enhanced (99%) compared to particle growth. For slow addition of reducing agent, the seeds do grow, but the product nanoparticle's degree of homogeneity in shape is compromised. For higher concentrations of seeds, nanoparticle growth is better controlled for slow addition of reducing agent compared ...
TL;DR: In this article, a review of the techniques used to produce optically functionalized mesostructured and mesoporous materials and the characterization of the final composites is presented.
Abstract: Mesostructured and mesoporous materials are emerging as a new class of optical materials. For mesostructured materials (inorganic/surfactant composites), prepared using a one-step synthesis procedure where the inorganic/surfactant/optically active species coassemble, the unique architecture provided by the surfactant-inorganic phase separation allows for higher concentrations compared to traditional sol-gel glasses and protective packaging of uniform three-dimensional arrays of optical species. The corresponding regularly arranged pores found in mesoporous materials (inorganic only) provide a high surface area to better disperse optically active components and allow for rapid diffusion for optical sensor applications. In this review, we discuss recent research results on the techniques used to produce optically functionalized mesostructured and mesoporous materials and the characterization of the final composites.
TL;DR: In this article, a morphogenetic mechanism based on self-assembled silicate surfactant rod-like micelles is proposed and explains well the controllability of the morphology.
Abstract: MCM-41 silica particles with several morphologies have been controllably synthesized with a basic medium. Nanospherical MCM-41 silica with an average size of 110 nm was produced through reaction of extremely low surfactant concentrations of CTAB with TEOS in the sodium hydroxide medium at 353 K, while a submicrometer-sized silica rod, 0.3−0.6 μm in diameter and 1 μm in length, and micrometer-sized oblate silica with nominal diameter around 1 μm were synthesized in aqueous ammonia, where the size and the morphology were controlled by varing the content of the solvent. A morphogenetic mechanism that is based on the deposition of self-assembled silicate surfactant rodlike micelles is proposed and explains well the controllability of the morphology.
TL;DR: In this article, the synthetic pathway follows the well-known sol−gel procedure, where the homogeneous combination of inorganic and organic moieties in a single-phase material provides unique possibilities to tailor the mechanical, electrical, and optical properties with respect to numerous applications.
Abstract: The homogeneous combination of inorganic and organic moieties in a single-phase material provides unique possibilities to tailor the mechanical, electrical, and optical properties with respect to numerous applications. The synthetic pathway follows the well-known sol−gel procedure. Nevertheless, the establishment of defined hybrid products necessitates a basic understanding of the underlying chemistry as well as of the parameters influencing the processing techniques. Modern spectroscopy provides versatile tools, e.g., multinuclear NMR experiments and Raman scattering to investigate the sol−gel processing of organo(alkoxy)silanes in their co-condensation reactions with main group or transition metal alkoxides as well as in their copolymerization reactions with each other or with organic molecules. This almost infinite modular design concept has led to the industrial application of coatings for transparent plastics, glasses, and metals to prevent these substrates from mechanical abrasion, permeation, or co...
TL;DR: In this paper, a short review describes the evolution of the nature of microporous solids and the related concepts that were at the origin of this evolution, including the creation of very large pores, their design from topological considerations, and the introduction of computational methods.
Abstract: This short review describes the evolution of the nature of microporous solids and the related concepts that were at the origin of this evolution. The paper begins with the different families of classical organically templated inorganic porous solids, their parameters of synthesis, the mechanisms of formation, their consequences, and their limits. From the latter, the concept of hybrid organic−inorganic frameworks is introduced as well as their tentative classification according to the decrease of the dimensionality of the inorganic subnetwork. The last part of the paper is devoted to the new trends in the field: the creation of very large pores, their design from topological considerations, and the introduction of computational methods.
TL;DR: In this article, three new "onium" salts have been used to prepare polystyrene−clay nanocomposites, two functionalized ammonium salts while the third is a phosphonium salt.
Abstract: Polystyrene−clay nanocomposites have been prepared using a bulk polymerization technique. Three new “onium” salts have been used to prepare the nanocomposites, two are functionalized ammonium salts while the third is a phosphonium salt. By TGA/FTIR, both ammonium and phosphonium treatments have been shown to degrade by a Hofmann elimination mechanism at elevated temperatures. TGA/FTIR showed that the phosphonium treatment is the most thermally stable treatment when compared to the two ammonium salts. The nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, strength and elongation at break, as a measure of the mechanical properties, thermogravimetric analysis, and cone calorimetry. The onset temperature of the degradation is increased by about 50 °C and the peak heat release rate is reduced by 27−58%, depending upon the amount of clay that is present. The mass loss rates are also significantly reduced in the presence of the clay.
TL;DR: The fabrication of magnetic composite core−shell particles and hollow spheres with tailored dimensions and compositions has been accomplished by a multistep (layer-by-layer) strategy as discussed by the authors.
Abstract: The fabrication of magnetic composite core−shell particles and hollow spheres with tailored dimensions and compositions has been accomplished by a multistep (layer-by-layer) strategy. Composite particles were prepared by coating submicrometer-sized anionic polystyrene (PS) latices with magnetite (Fe3O4) nanoparticle layers alternately adsorbed with polyelectrolyte from aqueous solution. The thickness of the deposited multilayers could be finely tuned with nanoscale precision, either by selection of the number of adsorption cycles performed or by the number of polyelectrolyte layers deposited between each nanoparticle layer (i.e., interlayer). As demonstrated by transmission electron microscopy, a marked improvement in the growth, uniformity, and regularity of the composite multilayers was achieved when the number of polyelectrolyte interlayers was increased from one [(poly(diallyldimethylammonium chloride) (PDADMAC)] to three [(PDADMAC/poly(styrenesulfonate) (PSS)/PDADMAC)]. Hollow, intact magnetic sphere...
TL;DR: In this paper, the synthesis and characterization of cobalt oxide thin films obtained by chemical vapor deposition (CVD) on indium tin oxide (ITO) substrates, using a cobalt(II) β-diketonate as precursor.
Abstract: The present work reports the synthesis and the characterization of cobalt oxide thin films obtained by chemical vapor deposition (CVD) on indium tin oxide (ITO) substrates, using a cobalt(II) β-diketonate as precursor. The complex is characterized by electron impact mass spectrometry (EI-MS) and thermal analysis in order to investigate its decomposition pattern. The depositions are carried out in a cold wall reactor in the temperature range 350−500 °C at different oxygen pressures, to tailor film composition from CoO to Co3O4. The crystalline nanostructure is evidenced by X-ray diffraction (XRD), while the surface and in-depth chemical composition is studied by X-ray photoelectron (XPS) and X-ray excited auger electron spectroscopy (XE-AES). Atomic force microscopy (AFM) is employed to analyze the surface morphology of the films and its dependence on the synthesis conditions. Relevant results concerning the control of composition and microstructure of Co−O thin films are presented and discussed.
TL;DR: In this article, the authors examined how bridged polysilsesquioxanes are prepared, processed, characterized, and used, and described how attaching several "inorganic" cross-linking trialkoxysilanes on organic bridging groups permits facile formation of network polymers and gels with high levels of chemical functionality.
Abstract: The class of hybrid organic−inorganic materials called bridged polysilsesquioxanes are used for everything from surface modifiers and coatings to catalysts and membrane materials. This paper examines how bridged polysilsesquioxanes are prepared, processed, characterized, and used. In particular, it describes how attaching several “inorganic” cross-linking trialkoxysilanes on organic bridging groups permits facile formation of network polymers and gels with high levels of chemical functionality. There are a number of synthetic entries into bridged polysilsesquioxane monomers that have allowed a multitude of different bridging groups to be integrated into xerogels (dry gels) or aerogels (supercritically dried “air gels”). Much of the research to date has been successfully focused on engineering of the size of pores through the choice of the bridging groups. For example, materials with some of the highest known surface areas in porous materials have been prepared, and parameters allowing control of the pore ...
TL;DR: The applicability of the layer-by-layer (LbL) technique for the formation of a range of polymer-core inorganic-shell particles and inorganic hollow spheres is demonstrated Titanium dioxide, silica, and Laponite nanoparticles were used as the inorganic building blocks for multilayer formation on polystyrene (PS) sphere templates Composite organic−inorganic particles were formed by the controlled assembly of the preformed nanoparticles in alternation with oppositely charged polyelectrolytes onto PS microspheres as discussed by the authors.
Abstract: The applicability of the layer-by-layer (LbL) technique for the formation of a range of polymer-core inorganic-shell particles and inorganic hollow spheres is demonstrated Titanium dioxide, silica, and Laponite nanoparticles were used as the inorganic building blocks for multilayer formation on polystyrene (PS) sphere templates Composite organic−inorganic particles were formed by the controlled assembly of the preformed nanoparticles in alternation with oppositely charged polyelectrolytes onto PS microspheres The influence of nanoparticle type, shape (spherical to sheetlike), and size (3−100 nm), and the diameter of the PS sphere templates (210−640 nm) on the formation of multilayer shells was examined by transmission and scanning electron microscopy In addition, the LbL technique for coating polymer spheres has been shown to be adaptable with small variations in the coating steps used to optimize the nanoparticle coatings of the different materials For example, the number of polyelectrolyte multilay
TL;DR: In this paper, the presence of paramagnetic iron in the matrix of polystyrene-clay nanocomposites has been investigated and shown to increase the onset temperature of thermal degradation.
Abstract: Polystyrene-clay and polystyrene-graphite nanocomposites have been prepared and used to explore the process by which the presence of clay or graphite in a nanocomposite enhances the thermal stability of polymers. This study has been designed to determine if the presence of paramagnetic iron in the matrix can result in radical trapping and thus enhance thermal stability. Nanocomposites were prepared by bulk polymerization using both iron-containing and iron-depleted clays and graphites, and they were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, and cone calorimetry. The presence of structural iron, rather than that present as an impurity, significantly increases the onset temperature of thermal degradation in polymer-clay nanocomposites. Intercalated nanocomposites show an iron effect, but this is less important for exfoliated systems. Polymer-graphite nanocomposites show no difference between iron-free and iron-containing nanocomposites, presumably because the iron is not nanodispersed in the graphite.
TL;DR: In this paper, the authors highlight the advances that have been made and identify some of the gaps in our current knowledge of these materials and discuss size quantization effects and semiconductor quantum dots.
Abstract: A diverse array of semiconductor-based composite materials have been prepared, characterized, and utilized in many applications ranging from photocatalysis, photovoltaic cells, photoelectrochromic displays, and light-emitting devices to sensors. The composite architectures (nanoarchitectures in many cases) are equally diverse. In this review, we highlight the advances that have been made and identify some of the gaps in our current knowledge of these materials. Size quantization effects and semiconductor quantum dots are also discussed.
TL;DR: In this paper, the specific surface areas of the MgO samples were determined by the BET technique, which gave a feature of high surface area generally larger than 100 m2/g.
Abstract: Mg(OH)2 nanocrystallines with rod-, tube-, needle-, or lamella-like morphologies have been synthesized by a hydrothermal reaction using different magnesium precursors and solvents as the reactants. The products appeared to have narrow size distributions with a monodisperse nature. Subsequent thermal decomposition at 450 °C gave nanosized MgO, which preserved well the morphological features of the Mg(OH)2 samples. The specific surface areas of the MgO samples were determined by the BET technique, which gave a feature of high surface area generally larger than 100 m2/g. The channels formed in the thermal dehydroxylation process may account for this feature of the MgO nanocrystallines.
TL;DR: In this article, the authors used six organophosphorus compounds chosen as model coupling molecules: phenylphosphonic and diphenylphphosphinic acids, their ethyl esters, and their trimethylsilyl esters.
Abstract: Titanium oxide particles were treated using six organophosphorus compounds chosen as model coupling molecules: phenylphosphonic and diphenylphosphinic acids, their ethyl esters, and their trimethylsilyl esters. The ability of all of these coupling molecules to modify the surface of the TiO2 particles was demonstrated by elemental analysis, thermogravimetric analysis, and nitrogen adsorption. The bonding modes on the surface were investigated by means of diffuse reflectance IR Fourier transform (DRIFT) and 31P solid-state MAS NMR spectroscopy. Upon irradiation in water, a marked trend to the photooxidative degradation of the anchored organophosphorus groups was evidenced, especially in the case of phosphinate groups.
TL;DR: In this paper, a metal-loaded single-walled carbon nanotubes (SWNTs) is presented, consisting of 10 wt % Pt on entangled SWNT bundles.
Abstract: We have prepared a novel material, consisting of Pt particles supported on purified single-walled carbon nanotubes (SWNTs), representing the first reported metal-loaded SWNT material. The material contains 10 wt % Pt on entangled SWNT bundles consisting of 20−100 nanotubes each. The average Pt particle size is 1−2 nm. High-resolution transmission electron microscopy (HRTEM) observations combined with electron energy-loss spectroscopy (EELS) indicate chemical bonding between Pt and the SWNT surfaces. This bonding is accomplished presumably by ion exchange on carboxylic acid sites created on the nanotube surfaces by slow wet oxidation in dilute HNO3. In addition, a simple SWNT purification scheme requiring no filtration was developed for the preparation of this material. The purification results in a well-defined structure for the metal support useful for investigating the role of this material as a heterogeneous catalyst and the effects of metal−support interactions (MSI). Preliminary kinetics measurements...