Nonlinear Dynamics of Complex Surface Reactions

许多环境或经济上重要的化学反应发生在催化表面上，例如汽车催化转化器中铂金属上的CO氧化。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。存在典型的压力和温度状态，其中例如混沌行为持续存在。 我们的第一个项目的目的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”。继续与以前的研究，我们计划研究图案的形成在铂上的CO氧化反应周期性强迫条件下通过气相。我们将把这些研究扩展到用微光刻技术制造的复合材料。此外，我们将利用我们的聚焦激光束来局部操纵和控制微光刻改性催化表面上的反应模式。 我们研究计划的另一个途径将利用超薄金属箔作为研究表面反应的催化剂。由于化学反应过程中产生的热量，这些箔弯曲，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，需要最少的设备和功率。将与感兴趣的行业进一步探讨这一点。 我们的第二个研究方向是走向另一个实际应用，重点是点蚀。我们的技术，椭圆显微镜，现在可以可视化的保护氧化物层的厚度变化周围的亚稳态点蚀不锈钢和其他合金的事件。与理论家合作，将进一步开发和分析这种腐蚀现象的模型。这些研究的目的将是找到表面活性剂，即使在很小的数量是能够抑制点蚀的发生，这可能是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.