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Electrocatalysis of the Oxygen Reduction in Alkaline Media: Comparison of Predominant Reaction Pathways on Various Electrode Materials
Electrocatalysis of the Oxygen Reduction in Alkaline Media: Comparison of Predominant Reaction Pathways on Various Electrode Materials
Tuesday, 7 October 2014: 08:00
Expo Center, 1st Floor, Universal 14 (Moon Palace Resort)
The electrochemical oxygen reduction reaction (ORR) in alkaline media has recently attracted much attention due to an increased interest to solid and liquid alkaline fuel cells. In this presentation we will compare three classes of materials: transition metal oxides of the perovskite family, Fe/N/C, and Pt/C in terms of their activity and selectivity in the ORR. By combining the rotating-ring-disc electrode (RRDE) study with microkinetic modeling we will try to understand whether the oxygen reduction on these materials follows a “direct” 4 e- path or the O2 molecule is first reduced to hydrogen peroxide and only then to water, and how the predominant reaction pathways depend on the electrode potential. RRDE measurements in the temperature range from 25 to 75°C will help us to better understand the reaction mechanism. Complementary study of the hydrogen peroxide oxidation/reduction will also be presented. Finally, we will speculate which reaction steps have to be accelerated in order to decrease the overpotential of the ORR.
Acknowledgements
The authors thank E. V. Antipov, S.Ya. Istomin and F.S. Napolskiy of the Moscow State University (Russia) for the synthesis and characterization of perovskite materials and for valuable discussions, P. Simonov of the Boreskov Institute of Catalysis (Novosibirsk, Russia) for supplying Sibunit Carbon, and Tokuyama Company for supplying alkaline ionomer. Financial support from CNRS (France), Russian Foundation for Basic Research, and European Commission within the FP7 FREECATS project is gratefully appreciated.
References
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