کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
221281 463382 2006 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Investigations of the catalytic properties of manganese oxides for the oxygen reduction reaction in alkaline media
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Investigations of the catalytic properties of manganese oxides for the oxygen reduction reaction in alkaline media
چکیده انگلیسی

The oxygen reduction reaction (ORR) was studied in KOH electrolyte on different manganese oxides, dispersed on a carbon powder (MnOx/C). The oxides were prepared by different methods, for producing MnO, Mn3O4 and MnO2 as major phases dispersed on the Vulcan XC-72 carbon. The oxides were characterized by XRD (X-ray diffraction) and in situ XANES (X-ray absorption near edge structure). The electrochemical measurements were made using cyclic voltammetry and steady state polarization curves carried out in an ultra-thin layer rotating ring/disk electrode. The results have shown lower activity for the ORR on the MnOx/C species compared to that on Pt/C, but higher activity compared to that of pure Vulcan carbon. Formation of HO2- involving 2e− per O2 molecule is the main path of the ORR in the studied MnOx/C catalysts but, at low overpotentials and rotation rates the number of electrons is raised to 4 due to the occurrence of a HO2- disproportionation reaction. Large differences of electrocatalytic activity were seen for the different oxide species, and these were related to the presence of a Mn(IV) phase and the occurrence of a mediation processes involving the reduction of Mn(IV) to Mn(III), followed by the electron transfer of Mn(III) to oxygen.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Electroanalytical Chemistry - Volume 590, Issue 2, 15 May 2006, Pages 152–160
نویسندگان
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