Molecular Interrogation of Coupled Electron- and Phase-Transfer Reactions

在化学系化学结构、动力学和机理A （CSDM-A）项目的支持下，犹他大学的Rodrigo Noriega、犹他大学的Henry White和芝加哥大学的Gregory Voth将研究耦合电子和相转移过程。在这些反应中，电子转移与离子或中性分子跨越相边界的传输一起发生，存在于各种工业过程和能量存储技术中。由于缺乏对这些多步骤过程中关键步骤中间体的分子尺度理解，因此理解这些反应具有挑战性。Noriega博士和他的团队将把超快光谱和电化学实验与定义良好的分子系统结合起来，用计算方法独立研究耦合电子和相转移反应。由此产生的对这些反应的洞察有可能影响能量储存和稀有金属离子分离。除了对学生进行研究培训外，该团队还将组织一年一度的研讨会，其中包括实验室演示和专业发展机会。复杂界面上的探针反应，即氧化还原活性分析物在电极上进行电子转移，同时由于其氧化态的不同溶解度而在两个不混相之间转移，将通过三相界面的伏安法、超快瞬态吸收光谱和多尺度电化学分子动力学模拟进行研究。为了通知和测试捕获分子尺度动力学和宏观结果的新模型，将采用将计算与跨越时间和长度数量级的光谱和电化学观察相结合的分层框架。溶剂化壳交换的能量学和动力学，包括界面上波动的作用，将通过相特异性电化学响应、控制静电条件下相边界处的时间分辨吸收和发射测量以及多尺度分子动力学模拟来确定。在系统地改变双电层结构的同时，在明确的界面上独立监测离子和电子转移电流，以及高效的恒电位电化学模拟，将确定三相界面上相关耦合电子和相转移反应的分子结构的作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Structure, Dynamics, and Mechanisms A (CSDM-A) Program in the Division of Chemistry, Rodrigo Noriega of the University of Utah along with Henry White from the University of Utah and Gregory Voth from the University of Chicago will study coupled electron and phase transfer processes. These reactions, where electron transfer occurs alongside the transport of ions or neutral molecules across a phase boundary, are present in a wide variety of industrial processes and energy storage technologies. Understanding these reactions is challenging due to the lack of molecular-scale understanding of intermediates at critical steps in these multistep processes. Dr. Noriega and his team will integrate ultrafast spectroscopy and electrochemistry experiments on well-defined molecular systems with computational methods to study coupled electron and phase transfer reactions independently. The resulting insight into these reactions has the potential to impact energy storage and rare metal ion separations. In addition to training students in research, the team will organize an annual workshop that includes lab demonstrations and professional development opportunities.Probe reactions at complex interfaces, whereby redox-active analytes undergo electron transfer with an electrode while also transferring between two immiscible phases due to the differential solubility of their oxidation states, will be studied with voltammetry at three-phase interfaces, as well as by ultrafast transient absorption spectroscopy, and multiscale electrochemical molecular dynamics simulations. To inform and test new models that capture molecular-scale dynamics and macroscopic outcomes, a hierarchical framework that combines computation with spectroscopic and electrochemical observation spanning orders of magnitude in time and length will be employed. The energetics and dynamics of solvation shell exchange, including the role of fluctuations at the interface, will be determined by correlating phase-specific electrochemical responses, time-resolved absorption and emission measurements at phase boundaries under controlled electrostatic conditions, and multiscale molecular dynamics simulations. Independently monitoring the ion- and electron-transfer currents at well-defined interfaces while systematically altering their electric double layer structure, along with efficient constant-potential electrochemical simulation, will identify the role of molecular structure of relevant coupled electron and phase transfer reactions at three-phase interfaces.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.