Combining SAXS and XAS To Study the Operando Degradation of Carbon-Supported Pt-Nanoparticle Fuel Cell Catalysts,ACS Catalysis

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Combining SAXS and XAS To Study the Operando Degradation of Carbon-Supported Pt-Nanoparticle Fuel Cell Catalysts
ACS Catalysis ( IF 11.3 ) Pub Date : 2018-06-19 00:00:00 , DOI: 10.1021/acscatal.8b01321
Mauro Povia ₁ , Juan Herranz ₁ , Tobias Binninger ₁ , Maarten Nachtegaal ₂ , Ana Diaz ₂ , Joachim Kohlbrecher ₃ , Daniel F. Abbott ₁ , Bae-Jung Kim ₁ , Thomas J. Schmidt _{1,

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Affiliation

In the last two decades, small-angle X-ray scattering (SAXS) and X-ray absorption spectroscopy (XAS) have evolved into two well-established techniques capable of providing complementary and operando information about a sample’s morphology and composition, respectively. Considering that operation conditions can often lead to simultaneous and related changes in a catalyst’s speciation and shape, herein we introduce a setup that combines SAXS and XAS in a configuration that allows optimum acquisition and corresponding data quality for both techniques. To determine the reliability of this setup, the latter was used to study the operando degradation of two carbon-supported Pt-nanoparticle (Pt/C) catalysts customarily used in polymer electrolyte fuel cells. The model used for the fitting of the SAXS curves unveiled the fractal nature of the Pt/C-electrodes and their evolution during the operando tests, and both X-ray techniques were complemented with control, ex situ transmission electron microscopy, and standard electrochemical measurements. Ultimately, the results obtained with this combined setup quantitatively agree with those reported in previous studies, successfully validating this apparatus and highlighting its potential to study the operando changes undergone by worse-understood (electro)catalytic systems.

中文翻译：

结合SAXS和XAS研究碳负载的Pt-纳米颗粒燃料电池催化剂的操作降解

在过去的二十年中，小角度X射线散射（SAXS）和X射线吸收光谱（XAS）已经发展成为两种成熟的技术，能够分别提供有关样品的形态和成分的互补信息和操作信息。考虑到操作条件通常会导致催化剂形态和形状的同时变化和相关变化，在此我们介绍一种将SAXS和XAS组合在一起的配置，该配置可为两种技术提供最佳的采集和相应的数据质量。为了确定这种设置的可靠性，使用后者来研究操作聚合物电解质燃料电池中常用的两种碳载Pt纳米粒子（Pt / C）催化剂的降解。用于拟合SAXS曲线的模型揭示了Pt / C电极的分形特性及其在操作测试过程中的演变，并且两种X射线技术均辅以对照，非原位透射电子显微镜和标准电化学测量。最终，通过这种组合设置获得的结果在数量上与先前研究中报道的结果一致，成功地验证了该设备并突出了其研究较差理解（电）催化系统发生的操作变化的潜力。

更新日期：2018-06-19

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