Nanostructured materials chemical reduction

In recent years, nanotechnology has opened a new window on the physical-chemical properties of semiconductor materials nanostructuration. The development of nanostructured materials (nanowires, nanotubes, nanoparticles etc.) enables improvements in the response and recovery times of the sensor signal, due to the reduction of gas diffusion effects in the bulk of the material. Additionally, the sensitivity and the sensor response are also improved by the changes in the conduction mechanisms at the nanoscale and, finally, the reduction of the dimensions of the device allows the reduction of the power consumption by the system. 

Chemical properties. Increased surface area increases the chemical activity of a material. For example, a metal in bulk form may not be a catalyst the same metal in nanoscale particles may be an excellent catalyst. Important research measures pH, oxidation and reduction characteristics, and surface properties. An important concern is how nanostructures can change the chemical mechanisms of such key processes as hydrolysis and catalytic responses as well as differing hydrophobic, hydrophilic, or amphipathic surface properties. The atomic structures of high-energy surface sites and various types of defect sites on nanocrystals are needed, as well as their effect on reactivity. An initial priority is to gain exploitable knowledge of the physical chemistry of various nanoparticle surfaces. 

When the size of a material is reduced to the nanoscale, their physical and chemical properties are dramatically changed. The separated nanostructure of polymer composites is expected to bring important improvements for polymer electronics because the size reduction of materials increases the contact surface area and lowers the interfacial impedance between the electrode and the electrolyte, and decreases the transport pathways for both electrons and ions (Shi et al., 2015). In addition, the mechanical properties for strain accommodation as well as the flexibility will be improved. A variety of nanostructures of polymer composites have been developed including zero-dimensional nanoparticles, one-dimensional nanowires/rods/belts, two-dimensional nanosheets/plates, and three-dimensional porous frameworks/networks. 

One very special type of shape control results in hollow nanoparticles of different geometries. In principle, the process is rather simple, in that a particle of any structure may serve as template that is coated by a layer of the desired metal. Subsequent removal of the inner template, either by calcination or by selective dissolution, will result in the formation of hollow nanostructures. Whilst this general technique can be applied to many types of material, one special application that involves only metals is as follows. In this case, silver nanocrystals of different shapes are coated by gold layers, via a simple chemical process based on the reductive power of elementary silver towards Au. ... 

Recent advances in nanofabrication provide a unique opportunity to develop efficient materials for BBSs. Nanoparticles and carbon nanotubes have been used as materials for electrodes in BBSs [9]. Nickel powders and both chemically and biologically produced palladium nanoparticles have been used for hydrogen production in an MFC [23-25]. fiu etal. demonstrated that nanostructured manganese oxide could also be used for oxygen reduction in an MFC [26], Finally,... 

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