Electronic properties, nanostructured materials

Electronic properties, nanostructured materials, 4-5 Electron redistribution phenomenon of d orbitals, 116-117 schematic, 117... 

Due to their high surface-to-volume ratio and size-dependent electronic properties nanostructured materials like NPs are good as catalysts. NPs of different sizes and structures can show significantly different catalytic activities and thus provides an opportunity to understand the structure-function relationship. NPs prepared usually in ensembles of NPs immobilized on an electrode. Thus the electrocatalytic property result of the average properties of the ensemble. Optimization of the catalyst requires increasing the number of sites available for the reaction to occur, shape and size effect of NP and composition of particles (in case of mixed metal... 

Enhancement of corrosion resistance can bring huge dividends, as nanostructured materials are also superior in mechanical and electronic properties. Nanostructured metals, which are expected to be stronger, harder and tougher, can provide very hard coatings that are more resistant to corrosion, useful for applications in defense armor, aerospace components, constraction equipment, medical devices, sports equipment, etc. Efforts are focused on the commercialization of nanostractured alloys (steel, cobalt alloys, etc.) as well as nanostroctured bulk metals (Cu, Ni, Zr, Ti, etc.). A number of leading research and development institutes and companies... 

C.J. Brabec, F. Padingcr, V. Dyakonov, J.C. Hummelen, R.A.J. Janssen, N.S. Sarieiltci, in Molecular Nanostructures, Proceedings of the International Winterschool on Electronic Properties of Novel Materials, Kirehbcrg 1998. 

The introduction of new synthetic techniques has led to the discoveries of many new electronic materials with improved properties [20-22]. However, similar progress has not been forthcoming in the area of heterogeneous catalysis, despite the accumulation of considerable information regarding structure-reactivity correlations for such catalysts [14-19]. The synthetic challenge in this area stems from the complex and metastable nature of the most desirable catalytic structures. Thus, in order to minimize phase separation and destruction of the most efficient catalytic centers, low-temperature methods and complicated synthetic procedures are often required [1-4]. Similar challenges are faced in many other aspects of materials research and, in general, more practical synthetic methods are required to achieve controlled, facile assembly of complex nanostructured materials [5-11]. 

Buckminsterfullerene, the most representative example among the fullerenes, have been extensively explored. Their intrinsic properties such as their size, hydrophobicity, three-dimensionality, and electronic properties have made them extremely promising nanostructures, offering interesting features at the interface of various scientific disciplines, ranging from material sciences207 to biological and medicinal chemistry.208-210... 

Similar monolayers have been prepared with a diversity of electroactive units with the ultimate goal of elucidating the subtle balance between the structural and the electronic factors that regulate interfacial electron transfer.5,9,10 In particular, these studies have focused their attention on the rationalization of the influence that the distance between the electrode surface and the redox centers as well as the nature of the linkers between them have on the rates of electron transfer. In parallel to these fundamental investigations, the ability of thiols to anchor electroactive units on metallic electrodes has also been exploited to fabricate a wealth of nanostructured materials with tailored functions and properties.6-8 Indeed, these convenient building... 

Tokumoto M,NarymbetovB, Kobayashi H, Makarova TL, Davydov VA, Rakhmanina AV, Kashevarova LS (2000) In Kuzmany H, Fink J, Mehring M, Roth S (eds) Electronic properties of novel materials - molecular nanostructures. American Institute of Physics, Melville, NY, p 73... 

J. Abraham, P. Whelan, A. Hirsch, F. Hennrich, M. M. Kappes, A. Vencelova, R. Graupner, L. Ley, M. Holzinger, D. Samaille, P. Bernier, Electronic Properties of Novel Materials Molecular Nanostructures (eds H. Kuzmany, J. Fink, M. Mehring, S. Roth), Proc XVIIth Int. Winterschool, Kirchberg, Austria,... 

In this section, the potential application for amyloid fibrils and other selfassembling fibrous protein structures are outlined. These include potential uses in electronics and photonics presented in Section 4.1, uses as platforms for the immobilization of enzymes and biosensors presented in Section 4.2, and uses as biocompatible materials presented in Section 4.3. Each of these applications makes use of the ability of polypeptides to self-assemble and form nanostructured materials, a process that can occur under aqueous conditions. These applications also seek to exploit the favorable properties of fibrils such as strength and durability, the ability to arrange ligands on a nanoscale, and their potential biocompatibility arising from the natural materials used for assembly. 

Both the discovery of new synthesis processes for nanostructured materials and the demonstration of the highly reactive properties of these materials have increased rapidly within recent years. The new synthesis processes have made available nanostructured materials in a wide variety of compositions of metal oxides and metals supported on metal oxides, which have led to recognition of their exceptional chemical, physical, and electronic properties. The objective of this review is to provide recent results on synthesis of nanostructured materials using the novel processes that were developed in these laboratories recently and to contrast them to other important, new methods. Because some of the most important applications of nanostructured materials are as catalysts for chemical processing, several key reports on enhanced catalytic reactivity of nanostructured grains will be discussed along with the pertinent theory responsible for controlling both activity and selectivity of these new catalysts. 

---