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首页> 外文期刊>Electrocatalysis >Identical-Location Transmission Electron Microscopy Study of Pt/C and Pt–Co/C Nanostructured Electrocatalyst Aging: Effects of Morphological and Compositional Changes on the Oxygen Reduction Reaction Activity
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Identical-Location Transmission Electron Microscopy Study of Pt/C and Pt–Co/C Nanostructured Electrocatalyst Aging: Effects of Morphological and Compositional Changes on the Oxygen Reduction Reaction Activity

机译：Pt / C和Pt-Co / C纳米结构电催化剂老化的相同位置的透射电子显微镜研究：形态和组成变化对氧还原反应活性的影响

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摘要

In this study, the activity for the oxygen reduction reaction (ORR) and the structural, morphological, and compositional changes of Pt, Pt3Co, and PtCo nanoparticles deposited on high surface area carbon (Vulcan XC72) are investigated after they were submitted to accelerated electrochemical aging tests. These tests consisted of stepping the potential in 1 min successively between potentials of 0.9 and 0.1 V vs. reversible hydrogen electrode (RHE) or between 0.9 and 0.6 V vs. RHE for 15 h in 1.0 M H2SO4 at 60 °C. Transmission electron microscopy, identical-location transmission electron microscopy, X-ray energy-dispersive spectroscopy analyses, and in situ X-ray absorption spectroscopy are used to characterize the changes in the morphological, compositional, and in the Pt 5d electronic states before and after the electrochemical aging tests. The experimental results show that the Pt/C and Pt–Co/C electrocatalysts are modified upon aging, following changes in particle size, geometry, and composition. The 0.9- to 0.6-V protocol is more aggressive in reducing the ORR activity, and this seems to be strongly related to the carbon corrosion and not to changes in the metallic particles. After the 0.9- to 0.1-V aging procedure, the ORR activity of the Pt/C particles is improved, while that of Pt3Co/C particles only slightly changes. In the case of Pt/C, these effects are related to the increase of the particle sizes, surface reconstruction, and, therefore, smaller oxide formation, which potentially induces an increase of the ORR activity. On the contrary, on Pt3Co/C, these positive effects are counterbalanced by a detrimental (and large) effect of Co dissolution.
机译：在这项研究中，研究了氧还原反应（ORR）的活性以及沉积在高表面积碳（Vulcan XC72）上的Pt，Pt3Co和PtCo纳米颗粒的结构，形态和组成变化，将它们进行了加速电化学处理老化测试。这些测试包括在60°C的1.0M H2SO4中，相对于可逆氢电极（RHE）在0.9至0.1V的电势之间连续步进1分钟，或相对于RHE在0.9至0.6V的电势之间连续步进15分钟。透射电子显微镜，等位透射电子显微镜，X射线能量色散光谱分析和原位X射线吸收光谱用于表征前后Pt 5d的形态，组成和Pt 5d电子态的变化电化学老化测试。实验结果表明，随着粒径，几何形状和组成的变化，Pt / C和Pt-Co / C电催化剂在老化后会发生改性。 0.9V至0.6V的方案在降低ORR活性方面更具侵略性，这似乎与碳腐蚀密切相关，与金属颗粒的变化无关。经过0.9到0.1V的老化过程后，Pt / C颗粒的ORR活性得到改善，而Pt3Co / C颗粒的ORR活性仅发生了微小变化。在Pt / C的情况下，这些影响与粒径的增加，表面重构以及因此较小的氧化物形成有关，这有可能导致ORR活性增加。相反，在Pt3Co / C上，这些积极作用被Co溶解的有害（大）作用所抵消。

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  • 来源
    《Electrocatalysis》 |2013年第2期|104-116|共13页
  • 作者

    Flávio R. Nikkuni; Edson A. Ticianelli; Laetitia Dubau; Marian Chatenet;

  • 作者单位

    Instituto de Química de São Carlos Universidade de São Paulo">(1);

    Laboratoire d’Electrochimie et de Physico-chimie des Matériaux et des Interfaces LEPMI-Phelma UMR 5279 CNRS/Grenoble-INP/Université de Savoie/Université Joseph Fourier">(2);

    Instituto de Química de São Carlos Universidade de São Paulo">(1);

    Laboratoire d’Electrochimie et de Physico-chimie des Matériaux et des Interfaces LEPMI-Phelma UMR 5279 CNRS/Grenoble-INP/Université de Savoie/Université Joseph Fourier">(2);

    Laboratoire d’Electrochimie et de Physico-chimie des Matériaux et des Interfaces LEPMI-Phelma UMR 5279 CNRS/Grenoble-INP/Université de Savoie/Université Joseph Fourier">(2);

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  • 关键词

    Electrocatalyst degradation; ILTEM; Oxygen reduction reaction; Platinum and platinum–cobalt alloy nanoparticles;

    机译：电催化剂降解;ILTEM;氧还原反应;铂和铂钴合金纳米颗粒;

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