Nanomaterial electrodeposited nanomaterials

Morris, D. G. Munoz-Morris, M. A. Relationships between mechanical properties, grain size, and grain boundary parameters in nanomaterials prepared by severe plastic deformation, by electrodeposition and by powder metallurgy methods. J. Metastable Nanocrystal. Mater. 15-16, 585-590 (2003). 

This critical compaction step is avoided in the case of the electrochemical route of pulsed electrodeposition (PED) [29] which transforms cations, i.e. atomic species, directly into nanomaterials without the detour via nanopartides. In this way densities up to 99% of the theoretical value can be achieved, such that these materials exhibit, for instance, intrinsic mechanical properties and not those dominated by voids. 

Usually there is a lot of effort required to make nanomaterials by electrochemical means. In aqueous solutions the electrodeposition of nanocrystalline metals requires pulsed electrodeposition and the addition of additives whose reaction mechanism hitherto has only been partly understood (see Chapter 8). A further shortcoming is that usually a compact bulk material is obtained instead of isolated particles. The chemical synthesis of metal or metal oxide nanoparticles in aqueous or organic solutions by colloidal chemistry, for example, also requires additives and often the desired product is only obtained under quite limited chemical conditions. Changing one parameter can lead to a different product. 

In ionic liquids the situation seems to be totally different. It was surprising to us that the electrodeposition of metals and semiconductors in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide delivers nanocrystalline deposits with grain sizes varying from 10 to 200 nm for the different materials, like Si, Al, Cu, Ag and In, investigated to date. It was quite surprising in the case of Al deposition that temperature did not play a tremendous role. Between 25 and 125 °C we always got nanocrystalline Al with similar grain sizes. Similar results were obtained if the deposition was performed in tri-hexyl- tetradecylphos-phonium bis (trifluoromethylsulfonyl) amide. Maybe liquids with saturated nonaromatic cations deliver preferentially nanomaterials this is an aspect which, in our opinion, deserves further fundamental studies. 

Common methods for the fabrication of metallic nanoparticle arrays are electron beam lithography, photolithography, laser ablation, colloidal synthesis, electrodeposition and, in recent time, nanosphere lithography for which a monodisperse nanosphere template acts as deposition mask. A review on advances in preparation of nanomaterials with localized plasmon resonance is given in [15]. 

However, it is only recently that the potential benefits of combining sonochemistry with electrochemistry have increasingly been studied. It should be noted that electrochemical methods, mainly electrodeposition, are well established for the preparation of metals and semiconductor nanomaterials (for a review see Mastai et al. [146]). 

However, the application of cobalt- oxide nanomaterials for immobilization of biomolecelus and biosensor fabrication is rare. Recently we used electrodeposited cobalt-oxide nanoparticles for immobilization of hemoglobin [67], The UV-visible spectrophotometric analysis and voltammetric studied indicates the immobilization of Hb onto cobalt-oxide nanoparticles (Figure 35). 

Abedin SZE, PoUeth M, Meiss SA et al (2007) Ionic liquids as green electrolytes for the electrodeposition of nanomaterials. Green Chem 9 549-553... 

Modes, G. and Rubinstein, I. (2001) Electrodeposition of semiconductor quantum dot films, in Electrochemistry of Nanomaterials (ed. G. Modes), Wiley-VCH Verlag GmbH, Weinheim, pp. 25-65. 

A number of processes are being used for producing nanomaterials for bulk production. The most common techniques used for synthesizing nanostructure materials include inert gas condensation, mechanical alloying, thermal spraying, electrodeposition, jet vapor deposition, vacuum thermal evaporation, and controlled chanical precipitation. 

This article reviews the capabilities and advantages of electrodeposition as a reliable and simple technique for the growth of semiconductor nanomaterials and fabrication of large-area... 

In spite of the exquisite control of reaction rate and duration afforded by electrochemical methods, electrodeposition has hardly been used for preparing nanomaterials. An exception to this generalization is the synthesis of nanoparticles and nanorods using the template synthesis method pioneered by Martin (1-6), Moskovits and co-workers (7-9), and Searson and co-workers (10-16). Template synthesis (Scheme 16.1.1) involves the electrodeposition of materials into the pores of ultrafiltration membranes (e.g., Nuclepore and Anopore ) that have uniform, cylindrical, or prismatic pores of a particular size. 

Metal deposited Templating membrane Electrodeposition conditions Nanomaterial obtained Note References... 

Carbon nanocoils, as well as carbon nanotubes, constitute a new class of carbon nanomaterials with properties that differ significantly from other forms of carbon. The structure of a nanocoil is similar to that of MWCNTs, except helical shape. The catalysts supported on carbon nanocoils exhibited better electrocatalytic performance compared with the catalyst supported on Vulcan XC-72 carbon. In particular, the Pt-Ru alloy catalyst supported on the CNC, which has both good crystallinity and a large surface area, showed a superior electrocatalytic performance, compared with other CNC catalysts [43]. A fuller-ene (Cso) film electrode was also suggested as a catalyst support for methanol oxidation after electrodeposition of Pt on these fullerene nanoclusters [44]. 

Similarly, ionic liquids are finding increasing use in the popular area of nanomaterials. Much of this effort is directed toward using ionic liquids as either solvents for the synthesis of nanomaterials (Nan and Liebscher) or their stabilization (Kraynov and Mueller). Electrodeposition and recovery of metals is a related and fairly mature field (Anicai, Florea, and Visan). 

A BCP is a good tool for the design of nanostractured materials, as discussed in the previous sections. It offers a flexible platform for a variety of nanomaterials with functionalities and robustness since one can combine BCP SA with a sol-gel process, nanoparticle synthesis, chemical vapor deposition, electrodeposition, or electroless deposition. Thus, in principle, the structural and material diversity obtained from the aforementioned techniques is substantial. This section introduces specific classes of material prepared from BCP-directed SA by the Wiesner group. 

It should be noted that anodic aluminum oxide templates are also frequently used to produce nanomaterials by sol-gel, by PVD or CVD techniques. Most straightforward is, however, electrodeposition for pore filling. 

---