Electrocatalytic Properties

The second form consists of Pt metal but the iridium is present as iridium dioxide. Iridium metal may or may not be present, depending on the baking temperature (14). Titanium dioxide is present in amounts of only a few weight percent. The analysis of these coatings suggests that the platinum metal acts as a binder for the iridium oxide, which in turn acts as the electrocatalyst for chlorine discharge (14). In the case of thermally deposited platinum—iridium metal coatings, these may actually form an intermetallic. Both the electrocatalytic properties and wear rates are expected to differ for these two forms of platinum—iridium-coated anodes. 

The electrocatalytic activity of novel redox films in regeneration of NAD/NADH has been investigated by means of chronoamperometry, hydrodynamic and potentiodynamic methods. In order to achieve the most efficient electrocatalytic properties indicated as both the highest heterogeneous rate constant and maximum sensitivity, the further optimization of electropolymerisation conditions has been made. 

Intensive research on the electrocatalytic properties of polymer-modified electrodes has been going on for many years Until recently, most known coatings were redox polymers. Combining redox polymers with conducting polymers should, in principle, further improve the electrocatalytic activity of such systems, as the conducting polymers are, in addition, electron carriers and reservoirs. One possibility of intercalating electroactive redox centres in the conducting polymer is to incorporate redoxactive anions — which act as dopants — into the polymer. Most research has been done on PPy, doped with inter alia Co 96) RyQ- 297) (--q. and Fe-phthalocyanines 298,299) Co-porphyrines Evidently, in these... 

The use of adatoms of foreign metals obtained by imderpotential deposition on the platinum surface is another convenient method for investigating the effect of a promoter on the electrocatalytic properties of platinum. However, the effect of adatoms in this case has been shown to be not as effective for electrooxidation of methanol as for the oxidation of other organic molecules such as formic acid adatoms of tin, however, showed a positive effect on the rate of methanol oxidation. ... 

Reduction of Carbon Dioxide Electrocatalytic Properties of Carbon 19... 

Electrocatalytic Properties of Carbon Materials Tarasevich, M. R. Khrushcheva, E. I. 19... 

Multipods and Dendritic Nanoparticles of Platinum Colloidal Synthesis and Electrocatalytic Property... 

Once we have developed our basic model and shown how it may be used to estab-hsh trends in electrochemical reactivity, we will take the further step of applying it to the identification of new bimetallic electrocatalysts. We will introduce simple procedures to rapidly screen bimetallic alloys for promising electrocatalytic properties, and we will demonstrate the importance of including estimates of the alloys stabihty in the screening procedure. Finally, we will give examples of successful apphcation of this method to specific problems in the area of electrocatalyst development. 

Adzic RR. 1984. Electrocatalytic properties of surfaces modified by foreign metal adatoms. In Gerisher H, Tobias CW, eds. Advances in Electrochemistry and Electrochemical Engineering. Volume 13. New York Wiley-Interscience. pp. 159-260. 

Gromyko VA, Khazova OA, Vassiliev YB. 1976. The differences in adsorption and electrocatalytic properties of smooth and platinized platinum. Elektrokhimiya 12 1352-1357. 

The Effect of Structurally Well-Defined Pt Modification on the Electrochemical and Electrocatalytic Properties of Ru(0001) Electrodes... 

In this section, we focus on the Pt-induced modifications of the electrocatalytic properties of Ru(OOOl), using the electro-oxidation of CO (CO bulk oxidation) as example. 

The influence of Pt modihcations on the electrochemical and electrocatalytic properties of Ru(OOOl) electrodes has been investigated on structurally well-defined bimetallic PtRu surfaces. Two types of brmetalhc surfaces were considered Ru(OOOl) electrodes covered by monolayer Pt islands and monolayer PtRu/Ru(0001) surface alloys with a highly dispersed and almost random distribution of the respective surface atoms, with different Pt surface contents for both types of structures. The morphology of these surfaces differs significantly from that of brmetaUic PtRu surfaces prepared by electrochemical deposition of Pt on Ru(0001), where Pt predominantly exists in small multilayer islands. The electrochemical and electrocatal5d ic measurements, base CVs, and CO bulk oxidation under continuous electrolyte flow, led to the following conclusions ... 

Another type of model electrode uses multilayer electrolytic deposits, which attracted the interest of electrochemists long before physical methods for their structural characterization were introduced. These electrodes were usually characterized by their roughness factors rather than particle size, the former being of the order of 10 -10 (for original references, see the review [Petrii and Tsirhna, 2001]). Multilayer electrolytic deposits have very complex stmctures [Plyasova et al., 2006] consisting of nanometer-sized crystallites joined together via grain boundaries, and hence have very pecuhar electrocatalytic properties [Cherstiouk et al., 2008] they will not be considered further in this chapter. 

Savinova ER, Lebedeva NP, Simonov PA, Kryukova GN. 2000. Electrocatalytic properties of platinum anchored to the surface of highly oriented pyrolytic graphite. Russ J Electrochem. 36 (9) 952-959. 

Takasu Y, Eujii Y, Yasuda K, Iwanaga Y, Matsuda Y. 1989. Electrocatalytic properties of ultra-fine platinum particles for hydrogen electrode reaction in an aqueous solution of sulfuric acid. Electrochim Acta 34 453-458. 

Heme-contaming dehydrogenase enz5mes are promising for technological applications, and as more enzymes are isolated and smdied, it is likely that systems with further attractive electrocatalytic properties will be uncovered. 

Vincent KA, Parkin A, Armstrong FA. 2007. Investigating and exploiting the electrocatalytic properties of hydrogenases. Chem Rev 107 4366-4413. 

Postlethwaite TA, Hutchison JE, Hathcock KW, Murray RW. 1995. Optical, electrochemical and electrocatalytic properties of self-assembled thiol-derivatized porphyrins on transparent gold-hlms. Langmuir 11 4109. 

The electrocatalytic properties of several parent dinitrogen or hydrazido-containing molybdenum and tungsten complexes with dppe ligand have also been investigated. Each of these complexes yielded NH3, in chemical yields which ranged from 1% to 36% per mole of complex.318... 

A number of mechanistic pathways have been identified for the oxidation, such as O-atom transfer to sulfides, electrophilic attack on phenols, hydride transfer from alcohols, and proton-coupled electron transfer from hydroquinone. Some kinetic studies indicate that the rate-determining step involves preassociation of the substrate with the catalyst.507,508 The electrocatalytic properties of polypyridyl oxo-ruthenium complexes have been also applied with success to DNA cleavage509,5 and sugar oxidation.511... 

A.V. Kashevskii, J. Lei, A.Y. Safronov, and O. Ikeda, Electrocatalytic properties of meso-tetraphenylporphyrin cobalt for nitric oxide oxidation in methanolic solution and in Nafion film. J. 

S.M. Chen and C.J. Liao, Preparation and characterization of osmium hexacyanoferrate films and their electrocatalytic properties. Electrochim. Acta 50, 115-125 (2004). 

S.-M. Chen, Characterization and electrocatalytic properties of cobalt hexacyanoferrate films. Electrochim. Acta 43, 3359-3369 (1998). 

The first CNT-modified electrode was reported by Britto et al. in 1996 to study the oxidation of dopamine [16]. The CNT-composite electrode was constructed with bro-moform as the binder. The cyclic voltammetry showed a high degree of reversibility in the redox reaction of dopamine (see Fig. 15.3). Valentini and Rubianes have reported another type of CNT paste electrode by mixing CNTs with mineral oil. This kind of electrode shows excellent electrocatalytic activity toward many materials such as dopamine, ascorbic acid, uric acid, 3,4-dihydroxyphenylacetic acid [39], hydrogen peroxide, and NADH [7], Wang and Musameh have fabricated the CNT/Teflon composite electrodes with attractive electrochemical performance, based on the dispersion of CNTs within a Teflon binder. It has been demonstrated that the electrocatalytic properties of CNTs are not impaired by their association with the Teflon binder [15]. 

Clays are usually cation-exchangeable aluminosilicates, and exfoliated clay particles have a platelet shape with nanoscopic size. Cast protein-clay films on electrodes have been used to immobilize proteins. The Clay/Mb electrode has good electrocatalytic properties for the reduction of oxygen and hydrogen peroxide [236] and the biosensors can also be made based on these properties. 

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