Electrocatalysis of oxygen reduction

Bettelheim, A.; Chan, Ray J.H.; Kuwana, Theodore

doi:10.1016/s0022-0728(79)80107-2

Cited by 87 publications

(46 citation statements)

References 16 publications

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“…According to McIntyre and Peck, "current or kinetic saturation" occurs as the time for an oxygen molecule to traverse through the convective diffusion layer becomes comparable to the time required to diffuse across the surface to an active site [22]. The thickness (6) of the convective diffusion layer at a rotating-disc electrode (RDE) is given by S = 1 6l~i/3,,i/6~-1/* (I) where D is the diffusion coefficient of the electroactive species, v is the kinematic viscosity of the electrolyte and w is the rotational speed of the electrode_ The time (7) to traverse this layer can be calculated as ,r= 1.3D-'/3y'/3w-' (2) For curve 3 of Fig. 9 deviation of the Levich behaviour is already visible for a rotation frequency of 16 s-l. For this rotation frequency the time required to pass through the diffusion layer is 0.12 s, with v = 1.065 X lo-' cm2 s-* and D = 1.36 X lo-' cn?…”

Section: Oxygen Reduction On Cotspcmentioning

confidence: 99%

The cathodic reduction of oxygen at metal tetrasulfonato-phthalocyanines: influence of adsorption conditions on electrocatalysis

Elzing

Putten

Visscher

et al. 1987

Journal of Electroanalytical Chemistry and Interfacial Electroc

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Section: Oxygen Reduction On Cotspcmentioning

confidence: 99%

The cathodic reduction of oxygen at metal tetrasulfonato-phthalocyanines: influence of adsorption conditions on electrocatalysis

Elzing

Putten

Visscher

et al. 1987

Journal of Electroanalytical Chemistry and Interfacial Electroc

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“…dissociation 1501, or dismutation [51] of adsorbed 0,H). It has been found that in many, though not all, cases 0, reduction is associated with the (presumably) Me"/Me"' redox transition in the adsorbed or attached chelate [49,[52][53][54][55][56][57][58][59]. Unfortunately it has not been possible to study the Me"/Me"l redox process in our catalysts by cyclic voltammetry or differential pulse polarography owing to the high background currents of the active carbon support.…”

Section: Potential Of the Central Metal Ionmentioning

confidence: 99%

Oxygen Reduction on Transition‐Metal Porphyrins in Acid Electrolyte I. Activity

Veen

Baar

Kroese

et al. 1981

Ber Bunsenges Phys Chem

107

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The oxygen reduction characteristics of metalloporphyrins adsorbed at monolayer levels on a high surface area carbon, Norit BRX, have been studied in 8 N H,SO, and also in 6 N KOH. In an acid, oxygen reduction activity is found to be correlated with the Me"/Me"' redox potential. Most Co complexes have too high a redox potential, while too low a redox potential is observed for Fe, Ru, Os, Mn, and Cr. Ir porphyrins have the highest activity. In KOH, Ru porphyrins show the best performance. A heat treatment improves activity and stability strongly in an acid, but only mildly in an alkaline solution. A mechanism is proposed for oxygen reduction on transition metal chelates, both in acid and in alkaline solutions.

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“…30 Other complexes are also known as the most important components in sensors used for the electrocatalytic determination of oxygen dissolved in solution, 31 and as very effective catalysts for dioxygen electroreduction. 32,33 Moreover, non-water-soluble Co(II) porphyrin derivatives are attractive synthetic models of hemoglobin and myoglobin natural systems, owing to their unusual ability to form reversible dioxygen complexes. 34 Cationic Co III TMpyP (4) can produce breaks in DNA in the presence of a variety of oxidizing agents.…”

Section: Introductionmentioning

confidence: 99%

Resonance Raman characterization of cationic Co(II) and Co(III) tetrakis(N‐methyl‐4‐pyridinyl)porphyrins in aqueous and non‐aqueous media

Терехов

Kruglik

Malinovskii

et al. 2003

J Raman Spectroscopy

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Resonance Raman (RR) spectra of Co(II) and Co(III) complexes of the water-soluble cationic tetrakis(Nmethyl-4-pyridinyl)porphyrin [Co II TMpyP(4), Co III TMpyP (4)] were obtained in aqueous and non-aqueous media, using both B-and Q-band excitation wavelengths. RR spectra of Co II TMpyP(4) are observed for the first time, and they are compared with those of Co III TMpyP(4). Wavenumbers of the n 2 , n 4 , n 8 and n 6 oxidation state-sensitive bands depend on pH in aqueous solution and on the nature of the solvent ( methanol, ethanol, DMF, DMSO): they lie in distinct spectral ranges for Co(II) vs Co(III) porphyrins. In addition, wavenumber shifts induced by axial ligation cover regions twofold broader for Co III TMpyP(4) than for Co II TMpyP(4). This shows that the electronic influence of axial ligands on the p-system of the macrocycle is more effective when cobalt is in a higher oxidation state. This can be due to (i) smaller axial bond lengths of Co(III) porphyrin and, hence, more efficient cobalt-axial ligand interaction as compared with Co(II) complexes, and (ii) Co III TMpyP(4) being involved in bis-adducts whereas Co II TMpyP(4) ismainly bound with only one axial ligand. The response of the porphyrin ring to the binding of axial ligands having various electron-donating-withdrawing properties was monitored by the behaviour of these oxidation-state sensitive RR bands: their shifts observed in a series of solvents were compared with Gutmann donor and acceptor numbers (DN, AN) of the solvents. A linear positive correlation was observed between Gutmann AN and n 2 , n 4 , n 8 and n 6 band wavenumbers for Co III TMpyP(4), whereas a linear negative correlation was observed for the same bands of Co II TMpyP(4) when DN increases. This means that enhanced electron-accepting properties of axial ligand result in a scarcity of cobalt d p -orbitals, which in turn leads to a decrease in p back-donation from cobalt to the porphyrin macrocycle.

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Electrocatalysis of oxygen reduction

Cited by 87 publications

References 16 publications

The cathodic reduction of oxygen at metal tetrasulfonato-phthalocyanines: influence of adsorption conditions on electrocatalysis

The cathodic reduction of oxygen at metal tetrasulfonato-phthalocyanines: influence of adsorption conditions on electrocatalysis

Oxygen Reduction on Transition‐Metal Porphyrins in Acid Electrolyte I. Activity

Resonance Raman characterization of cationic Co(II) and Co(III) tetrakis(N‐methyl‐4‐pyridinyl)porphyrins in aqueous and non‐aqueous media

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