Targeted design of α-MnO2 based catalysts for oxygen reduction. (10th February 2016)

• Record Type: Journal Article
• Authors: Lehtimäki, Matti; Hoffmannová, Hana; Boytsova, Olga; Bastl, Zdeněk; Busch, Michael; Halck, Niels Bendtsen; Rossmeisl, Jan; Krtil, Petr
• Is Part Of: Electrochimica acta. Volume 191(2016)
• Page Start: 452
• Page End: 461
• Publication Date: 2016-02-10
• Subjects: Electrocatalysis -- Oxygen reduction -- MnO2 -- DFT -- Rational design; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.01.070
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Abstract: The paper focuses on theoretical and experimental aspects of an oxide surface optimization for oxygen reduction reaction (ORR). Various doped α-MnO2 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-MnO2 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-MnO2 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.