Nonlinear Dynamics of Electrochemical Reaction Networks

化学系的化学结构、动力学和机理(CSDM-A)项目获得这一奖项，资助Istvan Z.Kiss教授和他在圣路易斯大学的研究小组研究电化学反应的模式形成。对于大多数在气态或液态条件下发生的化学反应，反应的原子或分子的数量稳步减少，产物原子或分子的数量稳步增加，直到反应完成(或者，我们说当它达到“平衡”时)。Kiss教授对所谓的振荡化学反应感兴趣，在这种反应中，某些物质的分子数量随着时间的推移而下降和上升。换句话说，反应有时是向前的，有时是反向的！振荡反应可以产生从蓝色到黄色再到蓝色的溶液，或者它们可以产生类似斑马条纹或豹斑的颜色图案。这种模式的形成是化学反应网络的一个例子，化学反应网络还没有完全被理解，但与生命系统如何进化和功能非常相关。Kiss教授的研究为振荡反应增加了另一个转折：他不只是在烧杯里将反应物混合在一起，而是用浸泡在溶液中的电极产生反应物。例如，镍电极可以以精确控制的速度产生镍离子(Ni(2+))。这意味着可以控制产生的振荡和模式，进而更好地理解化学网络行为。除了与生物系统相关外，这项研究还对电池和能源技术有影响。参与这个项目的研究生和博士后科学家沉浸在一个多学科的经历中，不仅涉及化学，还包括数据科学、数学和生物学。这个项目的总体目标是发现控制复杂的、远离平衡的电荷转移化学反应的自组织和图案形成的规律。该项目遵循三个轨道：1)微观尺度上的空间组织的电化学介质。对芯片实验室设备中形成的紧急网络进行了解码。微电极之间的耦合拓扑结构被用来识别具有简单平衡反应的新型动力学结构，包括金属溶解体系(Ni(0)/Ni(2+)，Cu(0)/Cu2+)和氢氧化反应。2)阴阳极相互作用：阴阳极相互作用的性质和结构由双极电极和串联电化学池决定。对本研究中建立的网络拓扑模型进行了测试，以验证其在描述电池单元动力学方面的有效性。3)设计的电化学网络上的嵌合体模式：电流产生反应的模块化网络是用已知的网络结构来构建的。通过改变每个模块中元素的数量和模块的数量，探索了同步模式本地化的弹性和可扩展性。除了前面提到的对学生和博士后研究人员的正式培训外，非线性化学动力学的演示正在被纳入本科课程，以及公共宣传活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With this award, the Chemical Structure, Dynamics and Mechanisms (CSDM-A) Program of the Division of Chemistry is funding Professor Istvan Z. Kiss and his research group at Saint Louis University to study pattern formation of electrochemical reactions. For most chemical reactions that occur in gaseous or liquid conditions, the reacting atoms or molecules steadily decrease in number, and the product atoms or molecules steadily increase in number until the reaction is complete (or, we say when it reaches "equilibrium"). Prof. Kiss is interested in so-called oscillating chemical reactions, in which the number of molecules of certain substances fall and rise with time. In other words, the reaction sometimes proceeds in the forward direction, and at other times in the reverse! Oscillating reactions can produce solutions that switch from blue to yellow color and back to blue, or they can produce patterns of color that may resemble zebra stripes or leopard spots. Such pattern formation is an example of chemical reaction networks, which are not yet fully understood but are very relevant to how living systems evolve and function. Prof. Kiss' research adds another twist to oscillating reactions: rather than just mixing reactants together in a beaker, he generates reactants with electrodes immersed in the solution. For example, nickel electrodes can generate nickel ions (Ni(2+)) at a precisely controlled rate. This means that the oscillations and patterns created can be controlled, and in turn the chemical network behavior better understood. In addition to its relevance to biological systems, this research also has implications for battery and energy technologies. The graduate students and post-doctoral scientists involved in this project are immersed in a multidisciplinary experience that spans not only chemistry, but data science, mathematics, and biology.The overarching objective of this project is to discover the laws that govern self-organization and pattern formation in complex, far-from-equilibrium charge transfer chemical reactions. The project is following three tracks: 1) Spatially Organized Electrochemical Media on the Microscale. The emergent networks that form in lab-on-chip devices are decoded. The coupling topology among the microelectrodes is used to identify novel types of dynamical structures with simple equilibrium reactions, including metal dissolution systems (Ni(0)/Ni(2+), Cu(0)/Cu(2+)) and the H2 oxidation reaction. 2) Cathode-Anode Interactions: The nature and structure of cathode-anode interactions are determined with bipolar electrodes and serially coupled electrochemical cells. Models of network topology developed in this study are tested for their utility in describing the dynamics of battery cells. 3) Chimera Patterns on Designed Electrochemical Networks: Modular networks of current generating reactions are built with known network configurations. The resilience and the scalability of the localization of the synchronization patterns are explored by changing the number of elements in each module and the number of modules. In addition to the aforementioned formal training of students and post-doctoral researchers, demonstrations of nonlinear chemical dynamics are being incorporated into the undergraduate curriculum, as well as public outreach events.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.