Nanostructured porous solids

The variety of porous solid materials that can be used as templates for nanostructure synthesis has been reviewed by Ozin (1992). In the template-assisted synthesis of nanowires, the pores or voids of the template are filled with the chosen material using a number of approaches. Nanowires have been derived via pressure injection, electrochemical deposition, and vapor deposition, as described in the following sections. 

This review focuses on the acid-base properties of surfaces of porous solids. In the context of the above discussion, it is inevitable that established practices will require some modifications. It is obvious that solids possess acidity and basicity. The challenge in characterizing their acid-base behavior results from the presence of two phases and from location of the acid-base sites at the interface between the solid and either a gaseous or liquid phase. Moreover, when acid-base chemistry occurs in spaces confined to the micropores or interlayers of nanostructured materials, the rules are broken a second time because all references to acid-base properties of macroscopically honlogeneous phases based on the classical approach become inconsistent. 

Galiy PV, Lesiv TI, Monastyrskii LS, Nenchuk TM, Olenych IB (1998) Surface investigations of nanostructured porous silicon. Thin Solid Films 318 113-116 Gaponenko N (2001) Sol-gel derived Aims in meso-porous matrices porous silicon, anodic alumina and artificial opals. Synth Met 124 125-130... 

Aprelev AM, Lisachenko AA, Laiho R, Pavlov A, Pavlova Y (1997) UV (hv = 8. 43 eV) photoelectron spectroscopy of porous silicon near Fermi level. Thin Solid Films 297 142-144 Arce RD, Koropecki RR, Olmos G, Gennaro AM, Schmidt JA (2006) Photoinduced phenomena in nanostructured porous silicon. Thin Solid Films 510 169-174... 

Koropecki RR, Arce RD, Schmidt JA (2004b) Infrared studies combined with hydrogen effusion experiments on nanostructured porous silicon. J Non Cryst Solids 338-340(1) 159-162 Koropecki RR, Arce RD, Gennaro AM, Spies C, Schmidt JA (2006) Kinetics of the photoinduced evolution of the nanostructured porous silicon photoluminescence. J Non Cryst Solids 352(9-20) 1163-1166... 

Mclnnes SJ, Irani Y, Williams KA, Voelcker NH (2012) Controlled drug delivery from composites of nanostructured porous silicon and poly(L-lactide). Nanomedicine (Lond) 7 995 Minko S (2008) Grafting on solid surfaces grafting to and grafting Irom methods. In Stamm M (ed) Polymer surfaces and interfaces. Springer, Berlin/Heidelberg, p 215 Mishra JK, Bhunia S, Baneijee S, Baneqi P (2008) Photoluminescence studies on porous silicon/ polymer heterostructure. JLumin 128 1169... 

The classical sol-gel drying process basis relies on solvent elimination from the matrix without generating a two-phase system and the related capillary forces that cause partial or total destruction of the gel nanostructure. If the liquid phase is removed from the gel in a nondestructive manner, a porous solid should be left behind with approximately the same shape and volume as the original gel. Several techniques have been developed and improved in order to obtain the best solid material from any given sol-gel process. Because of the extremely small pore sizes and the high surfeice area of the gel structure, the drying process has a tremendous impact on the properties [147] and economic key factors of the final material [148,149]. 

When it comes to characterizing catalysts, applying diffraction requires special attention. Many catalysts are formed by small active-phase particles supported in porous solids. These stmctures have a very limited spatial order. In these cases, the aspect of the diffraction pattern is very diffuse, which makes interpretation quite difficult. The application of X-ray diffiraction to characterize catalysts may range from simple identification of the phases through comparison with a database of reference patterns to simulation and refinement of nanostructures. Accordingly, it is essential to know the foundations of diffraction that contribute to the understanding of catalyst structures. 

We also include in this class of quasi-2D nanostructured materials Titania deposited inside ordered mesoporous silica (because an inner coating of mesoporous silica may be realized), or nano-dot type Titania particles well dispersed in the ordered porous matrix. We do not consider here solids which contain linear or zig-zag type TiOTiO-nanowires in a microcrystalline porous framework, such as ETS-4 and ETS-10, notwithstanding the interest of these materials also as photocatalysts,146-151 because these nanowires are located inside the host matrix, and not fully accessible from the gas reactants (the reactivity is essentially at pore mouth). 

Various nanoscale architecture can be designed, including solid spheres, hollow spheres, tubes, porous particles, solid particles, and branched structures (Table 2).To achieve such nanostructures, different fabrication methods are used depending on the types of material. The methods used for nanoscale assembly include molecular self-assembly, bioaggregation, nanomanipulation, photochemical patterning, molecular imprinting, layer-by-layer electrsostatic deposition, and vapor deposition. 

Porous silicon is compatible with standard silicon K-MOS technology and different microsystems based on this nanostructured material have been successfully fabricated [1], Porous silicon impregnating with solid state oxidants demonstrats combustion and explosion processes [2-5]. These processes can be used for various microactuators [6], In present work we have studied the influence of the porous silicon structure on the combustion and explosion processes. 

The book starts with a brief introduction to nanomaterials followed by chapters dealing with the synthesis, structure and properties of various types of nanostructures. There are chapters devoted to oxomolybdates, porous silicon, polymers, electrochemistry, photochemistry, nanoporous solids and nanocatalysis. Nanomanipulation and lithography are covered in a separate chapter. In our attempt to make each contribution complete in itself, there is some unavoidable overlap amongst the chapters. Some chapters cover entire areas, while others expound on a single material or a technique. Our gratitude goes to S. Roy for his valuable support in preparing the index manuscript. 

The template method for synthesizing nanostructures involves the synthesis of the desired material within the pores of a nanoporous membrane or other solid. This approach has been used in several experiments [224—229] for the preparation of Ti02 nanotubes and nanorods typically, porous aluminum oxide (PAO) nano-templates were used. 

Patermarakis, G. 2006. Aluminium anodizing in low acidity sulphate baths Growth mechanism and nanostructure of porous anodic films. Journal of Solid State Electrochemistry 10, 211-222. 

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