CAREER: Elucidating the Interfacial Structure of Complex Solvents for Chemical Transformations

作为吸附剂、助催化剂和电解质的高性能溶剂的可用性是先进技术（如二氧化碳的综合捕获和转化）的关键和未满足的需求。该项目将开发对二氧化碳具有高亲和力的功能化溶剂，并促进其有效转化为其他有用的产品，如燃料。这些复杂溶剂是含有高浓度盐的氢键有机络合物（HBOC）液体，通常具有分子尺度结构和非均质性。在这些溶剂中，二氧化碳在电极-电解质界面的吸收和反应机理尚不清楚。该项目将探索支撑吸收、界面液体结构和反应性的基本机制，为未来化学转化集成系统的设计提供信息。所获得的知识在分离、催化、传感器和其他电化学过程中具有深远的应用。通过这些应用，本研究解决了气候变化、减排、废物利用和能源消耗等社会挑战。本计划的教育目标是透过视觉效果提升学生的学习体验，并透过绘图培养学生的科学素养。本项目科学概念的视觉插图将被制作成教育材料，并将通过出版物、研讨会和公共活动传播。这些活动将促进团队合作，并通过与克利夫兰艺术学院的合作加强与克利夫兰当地社区的联系。在界面工程和电化学系统项目的支持下，该项目将表征带电表面界面处浓缩电解质的液体结构，并定量评估结构对分离过程和电化学反应中的电荷分布、热力学和反应机制的影响。二氧化碳模型化合物在HBOC电解质-电极界面内和界面处的溶剂化结构和反应状态将通过光谱学、中子和x射线反射率以及电分析技术进行研究。这些研究将为理解复杂溶剂中小分子的结构和动力学行为提供基础。更具体地说，将回答以下科学问题：(1)二氧化碳溶剂化物复合物在电极-电解质界面处的物理环境是什么？(2)界面结构对二氧化碳还原机制的电子、质子转移和选择性有何影响？本研究的结果将有助于理解HBOC电解质的电双层结构，因为它们不能用适用于稀释体系的传统模型来解释。研究结果也将对电解质在二氧化碳共催化中的作用的讨论产生影响。该项目将在本科和研究生阶段的课程和公众宣传中应用STEM教育理念“通过绘画学习”和艺术插图。通过绘画学习有望提高学生对工程课程的参与度，提高视觉素养，促进知识保留，增加追求stem相关领域的学生的多样性，并促进艺术和工程专业学生之间的跨学科交流。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。

The availability of high-performing solvents that function as absorbents, co-catalysts, and electrolytes is a critical and unmet need for advanced technologies such as integrated capture and conversion of carbon dioxide. This project will develop functionalized solvents that have high affinity to carbon dioxide as well as facilitate its efficient conversion to other useful products such as fuels. These complex solvents are hydrogen-bonded organic complex (HBOC) liquids with high concentrations of salts and often have molecular-scale structure and heterogeneity. The mechanisms of absorption and reactivity of carbon dioxide at the electrode-electrolyte interface are not well understood in these solvents. This project will explore the fundamental mechanisms that underpin absorption, interfacial liquid structure, and reactivity to inform future designs of integrated systems for chemical transformations. The knowledge gained has far-reaching applications in separations, catalysis, sensors, and other electrochemical processes. Through these applications, this research addresses the societal challenges of climate change, emission mitigation, waste utilization, and energy consumption. The educational goal of this CAREER project is to enhance students’ learning experience using visuals and to build science literacy through drawing. Visual illustrations of the scientific concepts of this project will be created for use as educational materials, which will be disseminated via publications, seminars, and public events. These activities will foster teamwork and strengthen ties with the local community in Cleveland through collaboration with the Cleveland Institute of Art.With support from both the Interfacial Engineering and Electrochemical Systems programs, this project will characterize the liquid structure of concentrated electrolytes at interfaces with electrified surfaces and quantitatively assess the structural impact on charge distribution, thermodynamics, and reaction mechanisms in separation processes and electrochemical reactions. The solvation structure and reactive state of the carbon dioxide model compound both within and at HBOC electrolyte-electrode interfaces will be investigated by spectroscopy, neutron and X-ray reflectivity, and electroanalytical techniques. These studies will provide a basis for understanding the structure and dynamics of the behavior of small molecules in complex solvents. More specifically, the following scientific questions will be answered: (1) What is the physical environment of the carbon dioxide solvate complex at the electrode-electrolyte interface? and (2) What is the impact of the interface structure on electron and proton transfer and selectivity of the carbon dioxide reduction mechanism? The results from this study will contribute to the understanding of electrical double layer structures of HBOC electrolytes, as they cannot be explained by the traditional models suitable for dilute systems. The results will also impact the discussions on the role of the electrolyte in carbon dioxide co-catalysis. The project will apply the STEM educational concept of ‘learning by drawing’ and artistic illustration in undergraduate and graduate-level courses and public outreach. Learning by drawing is expected to enhance student engagement in engineering courses, improve visual literacy, promote knowledge retention, increase diversity among students pursuing STEM-related fields, as well foster interdisciplinary communication between art and engineering students.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.