期刊
ELECTROCHIMICA ACTA
卷 55, 期 19, 页码 5349-5356出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.electacta.2010.04.062
关键词
Pt surface sites; Pt/C electrocatalysts; Cyclic voltammetry; Chemisorption; X-ray line broadening
资金
- DOE [DE-PS36-08G098009, DE-FG36-06G086041]
- Directorate For Engineering
- Div Of Industrial Innovation & Partnersh [0856055] Funding Source: National Science Foundation
Platinum surface atom (or site) concentrations for a series of commercially available 10, 20, and 40 wt% Pt/C electrocatalysts have been determined using X-ray diffraction (XRD), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), selective chemisorption, and cyclic voltammerry (CV) methods. Each method of analysis was repeated for a sufficient number of times to determine reproducibility and standard deviation limits. Comparison of the results shows that XRD and STEM methods give Pt surface site concentrations much higher than for chemisorption analysis due to assumptions regarding Pt particle shapes and particle size distributions. The results from CV analysis agree reasonably well with those from chemisorption if the sample amounts and methods of sample deposition preceding CV analysis can be well-controlled and there is no loss of surface exposure by the Nation over-layer. Because both chemisorption and CV analyses more directly measure actual site concentrations with fewer assumptions, these methods should be considered superior to XRD and STEM analyses. Further, since chemisorption uses substantially larger sample sizes (up to 0.25 g) compared to CV (<0.01 g), reliability of chemisorption data is much more reliable and should be considered as the metric for surface Pt site determination. (C) 2010 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据