Nanoparticle and Nanopore Materials

Growing requirements for safety and environmental controls has led to the development of voltammetric and amperometric methods for determination of explosives described in this chapter. Further development can be envisaged, especially in the field of nano-material-based electrochemical devices for detection of explosives, namely at graphene, carbon nanotubes, nanoparticles, and nanoporous materials, and composites of these materials. Electrochemical sensors offer rapid, sensitive, inexpensive, and reliable detection of explosive materials in any conceivable scenario. Coupling these attractive properties with the portable nature of electrochemical devices facilitates a wide range of decentralized applications. 

For a material that consists of small particles, the specific surface area increases considerably with decreasing particle size. Similarly, nanoporous materials exhibit high surface areas. Compare the two types of nanostructures (nanoparticles and nanopores) and describe why both lead to high values of specific surface area. 

Nanomaterials represent today s cutting edge in the development of novel advanced materials, which promise tailor-made functionality for unique applications in all important industrial sectors. Nanomaterials can be clusters of atoms, grains 100 nm in size, fibers that are less than 100 nm in diameter, films that are less than 100 nm in thickness, nanoholes, and composites that are a combination of these. In other words, it implies that the microstructures (crystallites, crystal boundaries) are nanoscale [1]. Nanomaterials include atom clusters, nanoparticles, nanotubes, nanorods, nanowires, nanobelts, nanofilms, compact nanostructured bulk materials, and nanoporous materials [2]. Materials in nanosize range exhibit... 

Naturally occurring nanomaterials exist in a variety of complex forms. In this chapter a short set of definitions will be stated for clarity. Nanocrystals are single crystals with sizes from a few nm up to about 100 nm. They may be aggregated into larger units with a wide spectrum of microstructures. Nanoparticles are units of minerals, mineraloids or solids smaller in size than 100 nm, and composed of aggregated nanocrystals, nanoclusters or other molecular units, and combinations of these. Nanoclusters are individual molecular units that have well-defined structure, but too small to be true crystals. Al and ZnsSs solution complexes are types of nanoclusters with sizes from sub nanometer to a few nm. Nanoporous materials are substances with pores or voids of nanoscale dimensions. These materials can be single crystals, such as zeolites or... 

SANS is useful in examining pore structures in nanoporous materials, or water in fractal networks (Li et al. 1994). Examples of aggregation-state analyses include studies of silica and titania nanoparticles (Hyeon-Lee et al. 1998), catanionic surfactants (Brasher and Kaler 1996) and Ti02-Si02 and Zr02-Si02 sol-gel materials (Miranda Salvado et al. 1996). Particle size distributions obtained via SANS, SAXS and TEM on nanophase Ti02-V02 catalyst particles are compared by Albertini et al. (1993). 

In heterogeneous systems Looking for an industrially accessible route to develop polymer nanoporous materials, other approaches were developed based on heterogeneous precursors (ie, systems in which heterogeneous nucleation takes place). On the one hand, addition of particles to the polymer (such as talc, titanium oxide, kaolin, nanosilica, and other nanoparticles) can increase the nucleation ratio [77-81]. The size of the individual particles is amain issue They should present a size of the same order of magnitude, or higher, than the critical nucleation radius of the polymer-C02 system [82]. In addition, the particles should be weU dispersed to increase the potential nucleation sites individual particle volumetric density should be of the same order, or higher, than the desired nucleation density. However, the low... 

Electrical conduction is also very important for many devices that exploit the huge area of surface or interface per unit volume in zero-dimensional nanostructured materials such as nanoporous materials, granular materials, nanocomposites, and nanoparticle assemblies. Examples of such devices are chemiresistor-type sensors, solar cells, light-emitting diodes, and energy-storage cells. From the point of view of electron... 

This article reviews the synthesis, characterization, and applications of rare earth oxide and snlphide nanomaterials. Special focus is placed on nanoparticulate materials and the description on nanoscale films and bulk nanoporous materials are intentionally excluded. In the first section, the synthesis methods of nanoparticles in general are reviewed, and examples of the production of rare earth oxides and sulphides are presented. The second section deals with the applications of rare earth oxides and sulphides, and they are discussed in relation to the unique properties of nanoscale particles. 

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