Electrocatalysis chlorine

Electrocatalysis of electrochemical chlorine evolution from Ru02-coated titanium anodes rests on the same grounds according to the so-called Krasil shchikov mechanism, which is schematically described by the reactions (8a) and (8b) for anodic chlorine evolution (9-/2) ... 

B. Electrocatalysis and Selectivity of Anodic Chlorine Evolution at Ru02-Anodes... 

Trasatti S. Electrocatalysis in the anodic evolution of oxygen and chlorine. Electrochim Acta. 1984 29 1503. 

Szpyrkowicz, L., M. Radaelli, and S. Daniele (2005). Electrocatalysis of chlorine evolution on different materials and its influence on the performance of an electrochemical reactor for indirect oxidation of poUutants. Catal. Today 100,425 429. 

Several reviews addressing the polarization behavior, d ion adsorption, competition between Cr adsorption and OH codeposition, oxide film formation, and cr ion discharge, as well as the kinetic aspects of the reaction on various oxide-covered and oxide-free surfaces that have been investigated during the past 15 years, have been published (55/, 333-338). Of these, particular mention should be made of Refs. 555, 335, 336, and 439-441, where the basic aspects of the properties of oxide electrodes and the kinetic aspects of oxide film formation in relation to Cl adsorption and the kinetics of Cr ion discharge were addressed. Mechanistic aspects of chlorine evolution were critically analyzed recently in an excellent article by Trasatti (338). In this article, the focus is primarily on the nature and characterization of the adsorbed intermediates partipatingin the course of CI2 evolution and their role in the electrocatalysis of the chlorine evolution reaction. As with the OER, in aqueous solutions CI2 evolution takes place on an oxidized surface of metals or on bulk oxide films, so that their surface states often have to be considered in treating the electrocatalysis of the reaction. 

The simplest isotherm in electrocatalysis is the electrochemical Langmuir isotherm. Considering, for example, the adsorption of chlorine atoms on a metal electrode, M, one can write ... 

Recent work has been carried out by Conway and Novak " " on the role of the oxide film, plus coadsorbed CP ion at Pt electrodes in the chlorine evolution reaction optimum electrocatalysis appears to arise at a surface at which appreciable coverage of specifically adsorbed Cl" ion exists together with an incomplete film of OH and O species. Thick oxide films on Ir and Ru electrodes are also very effective electrocatalysts. 

The difference between the low overpotential for chlorine and the high overpotential for oxygen avoids a significant oxygen evolution. DS A today can be used for more than 8 years before the coating has to be regenerated. For details of DSA, see essay Electrocatalysis of Chlorine Evolution. ... 

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