Electrocatalysis electrochemical reactors

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. 

Recent developments in material science, electrochemical reactor design, and electrocatalysis have led to an increasing number of electrolytic applications in the area of effluent treatment. These developments have allowed electrochemical treatment processes to become competitive with physicochemical and biological processes, in terms of both capital and operating costs. Some cost-competitive cases of electrochemical pollution control have appeared in the literature over the past several years [1-6]. 

Porous metallic structures have been used for electrocatalysis (Chen and Lasia, 1991 Kallenberg et al., 2007). Porous electrodes are made with conductive materials that can degrade under high temperatures at high anodic potential conditions. This last problem is of less importance for fuel cell anodes, which operate at relatively low potentials, but it can be of importance for electrochemical reactors. Porous column electrodes prepared by packing a conductive material (carbon fiber, metal shot) forming a bar are frequently used. Continuous-flow column electrolytic procedures can provide high efficiencies for electrosynthesis or removal of pollutants in industrial situations. Theoretical analysis for the electrodeposition of metals on porous solids has been provided by Masliy et al. (2008). 

Corrosion of the material used is another factor that limits the selection of the electrocatalyst. The electrochemical corrosion of pure noble metals is not as important as in the case of binary or ternary alloys in strong acid or alkaline solutions, since these catalysts are widely used in electrochemical reactors. In the case of anodic bulk electrolysis, noble metal alloys used in electrocatalysis mainly contain noble metal oxides to make the oxidation mechanism more favorable for complete electron transfer. The corrosion problem that occurs from this type of catalyst is the auto-corrosion of the electrode surface instead of the electrode/electrolyte solution interface degradation. The problem of corrosion is considered in detail in Chapter 22. 

Electrocatalysis and Electrochemical Reactors Constantines G. Vayenas and Symeon I. Bebelis... 

Association between enzymatic and electrochemical reactions has provided efficient tools not only for analytical but also for synthetic purposes. In the latter field, the possibilities of enzymatic electrocatalysis, e.g., the coupling of glucose oxidation (catalyzed either by glucose oxidase or glucose dehydrogenase) to the electrochemical regeneration of a co-substrate (benzoquinone or NAD+) have been demonstrated [171, 172]. An electroenzymatic reactor has also been developed ]172] to demonstrate how the enzyme-electrode association can be used to produce biochemicals on a laboratory scale. 

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