The locally-resolved reaction kinetics of CO oxidation on individual (100)-type grains of a polycrystalline Pt foil was monitored in situ using photoemission electron microscopy (PEEM). Reaction-induced surface morphology changes were studied by optical differential interference contrast microscopy and atomic force microscopy (AFM). Regions of high catalytic activity, low activity and bistability in a (p,T)-parameter space were determined, allowing to establish a local kinetic phase diagram for CO oxidation on (100) facets of Pt foil. PEEM observations of the reaction front propagation on Pt(100) domains reveal a high degree of propagation anisotropy both for oxygen and CO fronts on the apparently isotropic Pt(100) surface. The anisotropy vanishes for oxygen fronts at temperatures above 465 K, but is maintained for CO fronts at all temperatures studied, i.e. in the range of 417 to 513 K. A change in the front propagation mechanism is proposed to explain the observed effects.

中文翻译：

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通过 PEEM 绘制局部反应动力学：Pt 箔单个 (100) 型颗粒上的 CO 氧化


使用光电发射电子显微镜 (PEEM) 原位监测多晶 Pt 箔的单个 (100) 型颗粒上 CO 氧化的局部分辨反应动力学。通过光学微分干涉显微镜和原子力显微镜（AFM）研究了反应引起的表面形态变化。确定了 (p,T) 参数空间中的高催化活性、低活性和双稳定性区域，从而建立了 Pt 箔 (100) 面上 CO 氧化的局部动力学相图。 Pt(100) 域上反应前沿传播的 PEEM 观察揭示了明显各向同性 Pt(100) 表面上氧气和 CO 前沿的高度传播各向异性。在温度高于 465 K 时，氧气锋面的各向异性消失，但在所有研究温度（即 417 至 513 K 范围内）下，CO 锋面均保持各向异性。提出改变锋面传播机制来解释观察到的效应。