Silver-Platinum Bimetallic Catalysts for Oxygen Cathodes in Chlor-alkali Electrolysis: Comparison with Pure Platinum - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of The Electrochemical Society Année : 2003

Silver-Platinum Bimetallic Catalysts for Oxygen Cathodes in Chlor-alkali Electrolysis: Comparison with Pure Platinum

Résumé

New silver-platinum bimetallic oxygen reduction reaction (ORR) catalysts are investigated in alkaline media both for kinetics and stability aspects. Polycrystalline materials and carbon-supported nanoparticles (Pt/C and Ag-Pt/C) are compared. All catalyst active areas are evaluated by hydrogen adsorption voltammetry and transmission electron microscopy. ORR pathway, studied on a rotating ring-disk electrode, involves four electrons per oxygen molecule both on bimetallic and pure platinum catalysts in classical sodium hydroxide solution (1 M NaOH at 25°C). In industrial medium (11.1 M NaOH at 80°C), only three electrons are exchanged on bulk platinum resulting from partial peroxide formation; these peroxide ions are chemically decomposed in the active layer for carbon-supported catalysts leading to an apparent four-electron pathway. ORR is shown to be first order toward oxygen both in classical and industrial sodium hydroxide solutions. ORR kinetic parameters for silver-platinum bimetallic catalysts are comparable to platinum, even in industrial medium. Carbon-supported catalysts aging behaviors in industrial medium demonstrate the highly instable nature of Pt/C both in open-circuit and polarization, leading to particle growth and consequently to active area decrease. Conversely, Ag-Pt/C remains stable under the same aging conditions. Ag-Pt/C, stable and active, is therefore a suitable catalyst for the air cathode in the membrane chlor-alkali electrolysis process.
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Dates et versions

hal-00418019 , version 1 (17-09-2009)

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Marian Chatenet, Marc Aurousseau, Robert Durand, Françoise Andolfatto. Silver-Platinum Bimetallic Catalysts for Oxygen Cathodes in Chlor-alkali Electrolysis: Comparison with Pure Platinum. Journal of The Electrochemical Society, 2003, 150 (3), pp. D47-D55. ⟨10.1149/1.1540063⟩. ⟨hal-00418019⟩
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