کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6661812 | 1426556 | 2018 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The performance of structurally well-defined AgxPt1âx/Pt(111) surface alloys in the oxygen reduction reaction - An atomic-scale picture
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: The performance of structurally well-defined AgxPt1âx/Pt(111) surface alloys in the oxygen reduction reaction - An atomic-scale picture The performance of structurally well-defined AgxPt1âx/Pt(111) surface alloys in the oxygen reduction reaction - An atomic-scale picture](/preview/png/6661812.png)
چکیده انگلیسی
Aiming at a fundamental understanding of the performance of bimetallic electrodes in the oxygen reduction reaction (ORR), on an atomic scale and specifically of the role of Ag surface atoms in bimetallic PtAg electrodes in this reaction, we have investigated the properties of structurally well-defined AgxPt1âx/Pt(111) surface alloys with increasing Ag surface content in the ORR. Electrode surfaces with a well-known distribution of surface atoms were prepared and characterized by scanning tunneling microscopy under ultrahigh vacuum (UHV) conditions, and transferred in a controlled way, without contact to air, to a newly designed electrochemical flow cell setup. This allows us to determine the potential-dependent activity and selectivity of the ORR towards H2O or H2O2 under well-defined reactant mass transport conditions. We find a significant enhancement of the ORR activity for AgxPt1âx/Pt(111) surface alloys compared to Pt(111). From an analysis of the relative abundance of different types of AgxPt3âx trimer ensembles and simulations of the potential dependent activity of the different sites based on their Oad binding energy (J.K. Nørskov et al., J. Phys. Chem. B 108 (2004) 17886), the enhanced ORR activity can be related to AgPt2 surface sites, which are identified as most active sites, more active than Pt3 sites. Consequences of the excellent agreement between kinetic measurements and simulations based on calculated changes in the ORR thermodynamics induced by surface Ag on the validity of this approach are discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Electroanalytical Chemistry - Volume 819, 15 June 2018, Pages 401-409
Journal: Journal of Electroanalytical Chemistry - Volume 819, 15 June 2018, Pages 401-409
نویسندگان
Stephan Beckord, Sylvain Brimaud, R. Jürgen Behm,