Nanostructures nanowires

A common feature of the reconstructed (100) surfaces is that the reconstruction leads to a streaky appearance (Fig. 8), which suggests that they may constitute a template for the growth of one-dimensional nanostructures ( nanowires ). 

As for the nanostructures, ZnO nanostructures (nanowires, nanorods, etc.) provide a path to a new generation of devices, but a deliberate effort has to be made for ZnO nanostructures to be taken seriously for large-scale device applications, and to achieving high device density with accessibility to individual nanodevices. Reliable methods for assembling and integrating building blocks into circuits need to be developed. 

Tana ZM, LiJ, Li H, Li Y, Shen W Morphology-dependent redox and catalytic properties of CeOa nanostructures nanowires, nanorods and nanoparticles, Catal Today 148 (1-2) 179-183, 2009. 

There is considerable interest in developing new types of magnetic materials, with a particular hope that ferroelectric solids and polymers can be constructed— materials having spontaneous electric polarization that can be reversed by an electric field. Such materials could lead to new low-cost memory devices for computers. The fine control of dispersed magnetic nanostructures will take the storage and tunability of magnetic media to new levels, and novel tunneling microscopy approaches allow measurement of microscopic hysteresis effects in iron nanowires. 

One-dimensional (ID) nanostructures have also been the focus of extensive studies because of their unique physical properties and potential to revolutionize broad areas of nanotechnology. First, ID nanostructures represent the smallest dimension structure that can efficiently transport electrical carriers and, thus, are ideally suited for the ubiquitous task of moving and routing charges (information) in nanoscale electronics and optoelectronics. Second, ID nanostructures can also exhibit a critical device function and thus can be exploited as both the wiring and device elements in architectures for functional nanosystems.20 In this regard, two material classes, carbon nanotubes2131 and semiconductor nanowires,32"42 have shown particular promise. 

NW-TFT device performance does not change significantly upon slightly flexing the plastic substrate (Fig. 11.14d).67 The use of free-standing nanostructures for flexible electronics has also been demonstrated by various groups using nanotubes,68 nanowires,63 and nano- or micro-ribbons.69,70... 

This review will discuss the possibility to control and improve the reactivity of Titania by design of new tailored nano-architecture. Specifically, analyses quasi-ID Ti02 nanostructures, e.g. nanorods, nanowires and nanofibres, nanotubes and nanopillars. 2D Titania nanostructures, e.g. columnar-type films, ordered arrays of nanotubes or nano-rods/-wires, nanobowl array, nanomembranes (called also nanohole array) and nanosponge, and Ti-based ordered mesoporous matrices will be instead discussed in a consecutive review paper. 

We use the same approach to classify the different nanostructures for Titania. The term one-dimensional (ID) nanostructures indicate nanocrystals in which elongation only in one direction is above this threshold (about 10 nm). This class of ID nanostructures comprises different types of nano-ordered materials, such as nanorods, -wires, -coils, -fibers, -pillars (or -columns) and -tubes. We prefer to use the term quasi one-dimensional nanostructures, because often the dimensions are larger than the indicated threshold, although elongation along one main axis still exists. When the diameter of the nanorod, nanowire or nanotube becomes smaller, there is often a significant change in the properties with respect to crystalline solids or even two-dimensional systems. A bismuth nanowire is an excellent example, which transforms into a semiconductor, as the wire diameter becomes smaller.145... 

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). 

Research advances in the last few years have significantly progressed the possibility of developing new nanostructured Titania catalysts having controllable phase and architecture. This review is limited to quasi-1D Ti02 nanostructures, e.g. nanorods, nanowires and nanofibres, nanotubes and nanopillars. 

CuO nanostructures of variable shapes CuO nanospheres (5-10 run), CuO nanorods (WXL = 24-27 nmxl24-140 run) and CuO nanowires (WXL= 8-10 nmx230-270 nm) have been synthesised to study the effect of shape of the catalyst on the Cu(I)-catalyzed click azide-alkyne cycloaddition. Cu(I) species were generated in situ by the reduction of CuO nanostructures in the presence of sodium... 

The above sections should clearly demonstrate that the study of graphene and its hybrids, especially the latter, has only just begun. Hybrids of graphene with various inorganic nanostructures (nanoparticles, nanowires and nanosheets) are likely to possess many novel properties with potential applications. Graphene-MOF hybrids are yet to be explored extensively and they are found to reveal many useful properties. 

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