Nonlinear Dynamics of Complex Surface Reactions

许多对环境或经济具有重要意义的化学反应都发生在催化表面，如催化汽车转化器中铂金属的CO氧化反应。在一定的操作条件下，这些反应大多表现出非线性动力学系统的特征。例如，在典型的压力和温度机制中，混乱的行为持续存在。他说，我们第一个项目的目标是从理论和实验上探索控制和操纵表面反应的新方向，试图“驯服混沌”。在前人研究的基础上，我们计划研究在周期性强迫条件下，通过气相在铂上的CO氧化反应的花纹形成。我们将把这些研究扩展到通过微光刻技术制造的复合材料。此外，我们将利用我们聚焦的激光在微光刻修饰的催化表面上局部操纵和控制反应图案。此外，我们研究计划的另一条途径将利用超薄金属箔作为催化剂来研究表面反应。由于化学反应中产生的热量，这些薄片会弯曲，这种机械变形可以用作某些反应物的简单传感器。超薄金属箔将成为简单、廉价的“机械”仪器，用于以前所未有的低预算测量某些类型的反应速率，只需要最少的设备和功率。这一点将与感兴趣的行业进一步探索。他说，我们的第二个研究方向正在走向另一个实际应用，重点是点蚀。我们的技术椭圆显微镜现在可以可视化不锈钢和其他合金上亚稳态点蚀事件周围保护性氧化层厚度的变化。将与理论界合作，进一步开发和分析此类腐蚀现象的模型。这些研究的目的将是寻找表面活性剂，即使是少量的表面活性剂也能够抑制点蚀的发生，这可能具有巨大的经济和环境意义。

Many environmentally or economically important chemical reactions take place on catalytic surfaces, such as the CO-oxidation on platinum metals in catalytic automotive converters. Most of these reactions exhibit features of nonlinear dynamics systems under certain operating conditions. There are typical pressure and temperature regimes in which for instance chaotic behavior persists.        The aim of our first project is to explore, theoretically and experimentally, new directions in controlling and manipulating surface reactions, attempting the "taming of chaos". Continuing with previous research, we plan to study pattern formation in the CO oxidation reaction on platinum under periodic forcing conditions through the gas phase. We will be extending these investigations to composite materials created by microlithography. In addition, we will utilize our focused laser beam to locally manipulate and control reaction patterns on microlithographically modified catalytic surfaces.        Another avenue of our research program will utilize ultra thin metal foils as catalysts for studying surface reactions. Due to the heat produced during a chemical reaction these foils buckle and this mechanical deformation can be used as a simple sensor for certain reactants. Ultra thin metal foils will become simple inexpensive "mechanical" instruments for measuring certain types of reaction rates at an unprecedented low budget, requiring minimal equipment and power. This will be explored further with interested industries.        Our second research direction is moving towards another practical application, focusing on pitting corrosion. Our technique, Ellipso-Microscopy can now visualize changes of the thickness of the protective oxide layer surrounding metastable pitting events on stainless steels and other alloys. In collaboration with theoreticians, models of such corrosion phenomena will be further developed and analyzed. The aim of these studies will be to find surfactants, which, even in diminutive quantities are capable of suppressing the onset of pitting corrosion, which could be of enormous economical and environmental significance.