Surface area of nanomaterials

Abstract. Nanocarbon materials and method of their production, developed by TMSpetsmash Ltd. (Kyiv, Ukraine), are reviewed. Multiwall carbon nanotubes with surface area 200-500 m2/g are produced in industrial scale with use of CVD method. Ethylene is used as a source of carbon and Fe-Mo-Al- mixed oxides as catalysts. Fumed silica is used as a pseudo-liquid diluent in order to decrease aggregation of nanotubes and bulk density of the products. Porous carbon nanofibers with surface area near 300-500 m2/g are produced from acetylene with use of (Fe, Co, Sn)/C/Al203-Si02 catalysts prepared mechanochemically. High surface area microporous nanocarbon materials were prepared by activation of carbon nanofibers. Effective surface area of these nanomaterials reaches 4000-6000 m2/g (by argon desorption method). Such materials are prospective for electrochemical applications. Methods of catalysts synthesis for CVD of nanocarbon materials and mechanisms of catalytic CVD are discussed. 

While oxidation is mainly used for purification of carbon nanostructures, it may also be an efficient tool for size control and surface modification. By selectively oxidizing, for example, smaller carbon nanotubes or diamond crystals, it can provide a simple technique for narrowing size distributions in carbon nanomaterials. Finally, modification of the porosity (activation) of carbon is another example of controlled oxidation and may allow optimization of the pore structure and surface area of nanoporous carbide-derived carbon (CDC) for various applications. 

The application of nanocrystalline metal oxides in sensor devices is now well-established, and should produce benefits in terms of improved sensitivity and speed of response. On a similar note, nanomaterials have become increasingly important in battery technology, particularly in the development of lithium solid-state batteries [106, 303, 304]. Nanocrystalline oxides offer many advantages in SOFCs, primarily by increasing the surface area of the materials and hence the catalytic activity [305, 306], and this is especially important for lowering the cell s operating temperature. Overall, however, it remains clear that further research into the... 

Carbon nanotubes, due to their unique properties, have numerous applications, especially when conjugated with biomacromolecules. As far as the immobilization of proteins concerns, the high specific surface area of these nanomaterials facilitates the immobilization of more protein molecules on the carrier material, which is accompanied by an increased specific enzyme activity. 

Solvent effect on the textural properties of Ti02 samples is summarized in table 2. The use of cyclohexane improves the thermal stability and leads to better textural properties. Possibly the cyclohexane swells the micelles, making them larger, so increasing the pore size. The surface area increases up to 72% with CTMACl in cyclohexane after calcination at 773 K. A promising result, the crystallite sizes are lower in cyclohexane compared to etiianol whatever the surfactant employed. Using low cost soluble starch in cyclohexane, a surface area of 77 m. g is associated with 23 nm crystallites size. These nanomaterials are potential candidates to be used as support or as catalysts. 

Complete characterization includes determination of both the bulk and surface properties of nanomaterials, since both can influence impacts on the environment and biological systems. Bulk characterization consists of studying size, shape, phase, electronic stmcture, and crystallinity, while surface characterization looks at surface area, atomic structure, surface composition, and functionality. Specific examples of bulk and surface characterization methods are described below. 

Surface characterization techniques measure surface area and composition and stody surface reactivity of nanomaterials. The Braunner-Emmet-Teller (BET) method is used to measure surface area by adsorbing lutrogen on the surface of a... 

Bacterial infection is a common problem associated with orthopedic implantation procedures, causing serious complications in host tissues, failure of orthopedic implants, and even death of patients. Although antibiotics are widely used, problems of toxicity, antibiotic resistance, adverse responses of patients, short effective time, and availability always demand better approaches to prevent infection. Therefore, a new area of preventing infection has emerged by utihzing the extraordinary surface properties of nanomaterials (such as ultrasmall structures, increased surface area and roughness, increased grain boundaries, etc.) for antibiotic purposes. 

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