Reduction, electrocatalytic

Solid electrolyte fuel cells have been investigated intensively during the last four decades.10,33 37 Their operating principle is shown schematically in Fig. 3.4. The positive electrode (cathode) acts as an electrocatalyst to promote the electrocatalytic reduction of O2 (g) to O2 ... 

The isomerization of 1-butene to cis- and trans- 2-butene onPd/C/Nafion and Pd-Ru/Nafion electrodes is one of the most remarkable and astonishing electrochemical promotion studies which has appeared in the literature.39,40 Smotkin and coworkers39,40 were investigating the electrocatalytic reduction of 1-butene to butane on high surface area Pd/C and Pd-Ru cathodes deposited on Nafion 117 when, to their great surprise, they observed at slightly negative overpotentials (Fig. 9.31) the massive production of 1-butene isomerization, rather than reduction, products, i.e. cis- and trans-2-butenes. This is extremely important as it shows that electrochemical promotion can be used also to enhance nonredox catalytic reactions such as isomerization processes. 

Table 10.1. Dependence of the ratio of hydrogenation rates obtained by method B (presence of H and external potential control) and by method C (electrocatalytic reduction).5 ...

Alt H, Binder H, Sandstete G (1973) Mechanism of the electrocatalytic reduction of oxygen on metal chelates. J Catal 28 8-19... 

Toda T, Igarashi H, Watanabe M. 1998. Role of electronic property of Pt and Pt alloys on electrocatalytic reduction of oxygen. J Electrochem Soc 145 4185-4188. 

El-Deab MS, Ohsaka T. 2002b. An extraordinary electrocatalytic reduction of oxygen on gold nanoparticles-electrodeposited gold electrodes. Electrochem Commun 4 288-292. 

Armstrong FA, Bond AM, Buchi FN, Hanmett A, Hill HAO, Lannon AM, Lettington OC, Zoski CG. 1993. Electrocatalytic reduction of hydrogen-peroxide at a stationary pyrol3ftic-graphite electrode surface in the presence of cytochrome-c peroxidase— A description based on a microelectrode array model for adsorbed enzyme molecules. Analyst 118 973-978. 

Electrocatalytic reduction of both O2 and H2O2 starts at potentials close to that of the Fe couple in the absence of a substrate (which for most porphyrins is about 0.2-0 V with respect to a normal hydrogen electrode (NHE) at pH < 6 the exception being Fe(TMPyP), E k 0.5 V). Catalytic reduction of H2O2 by simple/erne porphyrins is too slow to be detectable in typical electrocatalytic experiments whereas ferrous porphyrins catalyze rapid reduction of H2O2,... 

Collman JP, Kaplun M, Sunderland CJ, Boulatov R. 2004b. Electrocatalytic reduction of ROOH. J Am Chem Soc 126 11166. 

Gadamsetti K, Swavey S. 2006. Electrocatalytic reduction of oxygen at electrodes coated with a bimetallic cobalt(II)/platinum(II) porphyrin. J Chem Soc Dalton Trans 5530. 

Electrocatalytic reduction of carbon dioxide to Q-C3 hydrocarbons with less than 0.2% electrochemical yield was reported154 at pH 7 in the presence of pyrocatechol, TiCl3, and Na2Mo04 at -1.55 V versus SCE. 

ELECTROCATALYTIC REDUCTION OF PROTONS AND HYDRIDE TRANSFER REACTIONS... 

Furthermore, it has been demonstrated that the successful electrocatalytic reduction of C02 with [Ru(bpy)2(CO)2]2+ in aqueous MeCN is mainly due to the formation of a polymeric electroactive film, which occurs during the reduction of the complex.91 This film is composed of an open cluster polymer [Ru(bpy)(CO)2]ra (Scheme 6) based upon extended Ru°—Ru° bonds. Electropolymerization of [Ru(bpy)2(CO)2]2+ results from the overall addition of two electrons per mole of [Ru(bpy)2(CO)2]2+ and is associated with the decoordination of one bpy ligand (Equation (33)). 

Other aza macrocyclic complexes, such as Schiff bases or tetraazaannulene derivatives, have been also used with some success for the electrocatalytic reduction of C02 in organic solvent in the presence of proton sources.166-168... 

ELECTROCATALYTIC REDUCTION OF DINITROGEN AND NITROGEN OXIDES 9.10.6.1 Electrocatalytic Activation of Dinitrogen... 

This process is of interest for the destruction of nitrate in water and nitrate electrocatalytic reduction offers a possible route to treat contaminated water. 

ELECTROCATALYTIC REDUCTION AND ACTIVATION OF DIOXYGEN 9.10.7.1 Electrocatalytic Four-electron Reduction of Dioxygen... 

S.R. Smith and H.H. Thorp, Application of the electrocatalytic reduction of nitric oxide mediated by ferrioxamine B to the determination of nitric oxide concentrations in solution. Inorg. Chim. Acta 273, 316-319(1998). 

This chapter presents an overview of the primary findings from 1970 to the present Hydrogenation using H2 as the reductant will be described, although there are examples of the electrocatalytic reduction of C02 [7-10] and the use of other reductants [11]. More detailed reviews on homogeneous hydrogenation of COz have been published, covering the years up to 1994 [12, 13] and from 1995 to 2003 [14]. 

The electrocatalytic reduction of dienes, like that of monoenes, is difficult when the double bond is not activated. Polyolefins with isolated double bonds cannot be reduced on mercury cathode, while double bonds conjugated to another -system can be reduced. 

DR. DAVID STANBURY (Rice University) With regard to the problem of the electrocatalytic reduction of oxygen, I have attempted to formalize some ideas regarding the constraints of thermodynamics in order to elucidate the probable character of cobalt complexes which may catalyze the oxygen electrode via binuclear peroxo-bridged intermediates. The following gross mechanism is presupposed ... 

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