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Article Dans Une Revue Journal of Applied Electrochemistry Année : 2002

Oxygen reduction on silver catalysts in solutions containing various concentrations of sodium hydroxide - comparison with platinum

Résumé

In air cathodes for chlorine–sodium hydroxide production, silver is a suitable catalyst for the oxygen reduction reaction (ORR), as is platinum. The ORR mechanism, studied with both rotating disc and ring-disc electrodes and impedance spectroscopy, is first order towards O2. However, the reaction can involve a direct four-electron or two-electron pathway. Although the latter involves different chemistry, including decomposition of hydrogen peroxide, the two pathways are difficult to distinguish, probably because they have the same rate-determining step. Considering kinetics/solubility ratios, temperature increase favours the ORR kinetics on both metals, whereas an increase in sodium hydroxide concentration is only positive for silver: for high sodium hydroxide concentration, platinum properties are hindered by greater adsorbed oxygenated species coverage. Thus, silver becomes competitive to platinum in high concentration alkaline media.

Domaines

Matériaux

Dates et versions

hal-00418100 , version 1 (17-09-2009)

Identifiants

Citer

Marian Chatenet, Laurence Géniès-Bultel, Marc Aurousseau, Robert Durand, Françoise Andolfatto. Oxygen reduction on silver catalysts in solutions containing various concentrations of sodium hydroxide - comparison with platinum. Journal of Applied Electrochemistry, 2002, 32 (10), pp. 1131-1140. ⟨10.1023/A:1021231503922⟩. ⟨hal-00418100⟩
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