1. Targeted design of α-MnO2 based catalysts for oxygen reduction.
- Author
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Lehtimäki, Matti, Hoffmannová, Hana, Boytsova, Olga, Bastl, Zdeněk, Busch, Michael, Halck, Niels Bendtsen, Rossmeisl, Jan, and Krtil, Petr
- Subjects
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MANGANESE dioxide , *MANGANESE catalysts , *OXYGEN reduction , *SURFACE chemistry , *HYDROTHERMAL synthesis , *OXIDATION states , *DENSITY functional theory - Abstract
The paper focuses on theoretical and experimental aspects of an oxide surface optimization for oxygen reduction reaction (ORR). Various doped α-MnO 2 based electrocatalysts were prepared by microwave-assisted hydrothermal synthesis and electrochemically characterized to validate density functional theory (DFT) based predictions of the oxidation state and local structure effects on the catalytic activity of α-MnO 2 catalysts in ORR. Both theory and experiments conclude that the highest activity in ORR is to be expected in the case of clustered Mn 3+ sites which yield activity comparable with that of the polycrystalline Pt. These active sites have to be formed under in-operando conditions and their formation is hindered in doped α-MnO 2 catalysts. The activity of the other conceivable active sites based on non-clustered Mn 3+ or Mn 4+ is inferior to that of clustered Mn 3+ . The activation of Mn 3+ or Mn 4+ based active sites leads to a shift in selectivity of the ORR process towards 2 electron formation of hydrogen peroxide. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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