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Surface diffusion of poisoning species during CO and formic acid oxidation on PtAu surface. The key role of the active site
Journal of Power Sources ( IF 9.2 ) Pub Date : 2020-11-16 , DOI: 10.1016/j.jpowsour.2020.229189
Daniela Minudri , Alvaro Y. Tesio , Florencia Fungo , Rodrigo E. Palacios , Paula S. Cappellari , Elena Pastor , Gabriel A. Planes

A comparative study of the Pt and Pt/Au surface towards CO and formic acid oxidation was performed by conventional electrochemical techniques used in combination with an electrochemical flow cell (four-electrode configuration) and in-situ Fourier Transform Infrared Spectroscopy. With this purpose, a polycrystalline Pt electrode was modified by spontaneous deposition of gold atoms, achieving a gold surface coverage (θ) in the range of 0 ≤ θ ≤ 0.47. Formic acid and carbon monoxide electrooxidation on polycrystalline Pt and Au-modified Pt surfaces were studied by cyclic voltammetry, linear sweep voltammetry, chronoamperometry and in-situ FTIR techniques. The electrochemical and in-situ FTIR evidence collected for CO and FA oxidation on Pt/Au support the idea of a strongly modified Pt surface. At the Pt/Au electrode, Au operates as a barrier between surface domains, and the main observable result is the uncoupling of the catalytic activity. The free (fast) surface diffusion of reactants at a low potential, which leads to characterize Ptpc as a “homogeneous surface” towards CO and FA oxidation, is not possible when Au is present.



中文翻译:

PtAu表面上CO和甲酸氧化过程中中毒物质的表面扩散。活动站点的关键作用

通过将传统的电化学技术与电化学流通池(四电极配置)和原位傅里叶变换红外光谱结合使用,对Pt和Pt / Au表面的CO和甲酸氧化进行了比较研究。为此,通过自发地沉积金原子来修饰多晶Pt电极,从而实现金表面覆盖率(θ)在0≤θ≤0.47的范围内。通过循环伏安法,线性扫描伏安法,计时安培法和原位FTIR技术研究了多晶Pt和Au修饰的Pt表面上的甲酸和一氧化碳电氧化。电化学和原位FTIR收集的关于Pt / Au上CO和FA氧化的证据支持强烈修饰Pt表面的想法。在Pt / Au电极上,Au作为表面之间的屏障,主要的观察结果是催化活性的解偶联。当存在Au时,反应物在低电势下的自由(快速)表面扩散会导致将Pt pc表征为朝向CO和FA氧化的“均匀表面”。

更新日期:2020-11-16
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