Electrocatalytic metal nanoparticles

Kou R, Shao Y, Mei D et al (2011) Stabilization of electrocatalytic metal nanoparticles at metal-metal oxide-graphene triple junction points. J Am Chem Soc 133 2541-2547... 

Mao and Mao invented a method for synthesizing supported metal catalysts with small metal nanoparticles (1-3 nm) even at high metal loadings (30-50 wt.%) [25]. The obtained metal catalysts exhibited superior electrocatalytic performance in fuel cells. In this invention, the unprotected metal nanocluster colloids prepared according... 

Leger, J.M., Preparation and activity of mono- or bi-metallic nanoparticles for electrocatalytic reactions. Electrochimica Acta, 2005. 50(15) p. 3123-3129. 

Electrocatalytic, photocatalytic, and photoelectrochemical behavior of a semiconductor modified by the deposition of metal nanoparticles depends strongly on the... 

On examination of the electrocatalytic activity of metal nanoparticles in dark electrode processes, of significant interest is the appearance of the limiting current on the i,V curve for the Cu-modified Ti02 electrode, especially taking into account that it does not depend on the stirring of electrolyte and cannot be considered as a consequence of any diffusion limitation caused by the electrolyte solution. At the same time, this limiting current is very sensitive to the heating of the electrolyte as well as to the IR illumination of the electrode. 

In a similar manner, during the process of the existing metal particles growth and the deposition of new species using cathodically biased electrode in a solution of metal ions, the growing metal phase will be also localized at the sites of the surface exposure of the continuous donor centers. The reason for this is that namely these sites possess substantially enhanced electrocatalytic activity in comparison with the stoichiometric oxide surface and exhibit the properties of current channels non-restricted by the Schottky barrier at the interface with the electrolyte. Actually, a peculiar decoration of the sites of donor centers accumulation and donor clusters localization by the metal nanoparticles takes place in the dark processes of metal particle deposition onto the surface of the chemically inert wide-band-gap oxides. The increased electrocatalytic activity of the wide-band-gap semiconductor electrodes resulted from the deposition of metal nanoparticles on their surface may be also regarded as a kind of such decoration . 

The features of the electrode used in this gas-phase electrocatalytic reduction of C02 are close to those used in PEM fuel cells [37, 40, 41] (e.g. a carbon cloth/Pt or Fe on carbon black/Nafion assembled electrode, GDE). The electrocatalysts are Pt or Fe nanoparticles supported on nanocarbon (doped carbon nanotubes), which is then deposited on a conductive carbon cloth to allow the electrical contact and the diffusion of gas phase C02 to the electrocatalyst. The metal nanoparticles are at the contact of Nation, through which protons diffuse. On the metal nanoparticles, the gas-phase C02 reacts with the electrons and protons to be reduced to longer-chain hydrocarbons and alcohols, the relative distributions of which depend on the reaction temperature and type of metal nanoparticles. Isopropanol forms selectively from the electrocatalytic reduction of C02 using a gas diffusion electrode based on an Fe/N carbon nanotube (Fe/N-CNT) [14, 39, 40]. Not only the nature of carbon is relevant, but also the presence of nanocavities, which could favor the consecutive conversion of intermediates with formation of C-C bonds. 

According to a different theoretical approach, the kinetics of oxygen on Pt catalysts were interpreted on the basis of the separation distance between metal nanoparticles. Pt crystallites, separated by less than about 20 nm, were observed to exhibit lower electrocatalytic activity because of either diffusion or a mutual... 

X. Zhang, F. Zhang, K.-Y. Chan, Synthesis of Pt Ru Mo ternary metal nanoparticles by microemulsions, their characterization and electrocatalytic properties, Journal of Materials Science, 39 (2004) 5845-5848. 

Conducting-polymer nanoparticles are a distinct structural morphology with aspect ratios of roughly 1 1 1. As is the case with other forms of nanoparticle, such as metallic and metal oxides, these materials have several potential physical and chemical benefits. They have high surface-area-to-volume ratios and high radii of curvature which drastically alter the surface morphology in comparison to bulk polymer strucmres. This effect, in common with other nanostmctures, may lead to enhancements of alterations in electrocatalytic processes. Nanoparticles can also be formulated to be stable suspensions, which can be processed as if they were a true solution. This has significant benefits for production and... 

One of the most applicable metal nanoparticles is gold nanoparticles which have been used in different fields. These applications are enzymatic biosensors based on gold nanoparticles and their applications in genosensors, immunosen-sors, and electrocatalytic chemosensors (Fredy, 2008). 

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