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

作为吸收剂、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产品，如燃料。这些络合物溶剂是具有高浓度盐的氢键有机络合物（HBOC）液体，并且通常具有分子级结构和不均匀性。在这些溶剂中，二氧化碳在电极-电解质界面处的吸收和反应性的机制尚不清楚。该项目将探索吸收，界面液体结构和反应性的基础机制，为化学转化集成系统的未来设计提供信息。所获得的知识在分离、催化、传感器和其他电化学过程中有着深远的应用。通过这些应用，这项研究解决了气候变化，减排，废物利用和能源消耗的社会挑战。这个CAREER项目的教育目标是利用视觉效果增强学生的学习体验，并通过绘画建立科学素养。将制作该项目科学概念的视觉插图，作为教育材料，通过出版物、研讨会和公共活动传播。这些活动将通过与克利夫兰艺术学院的合作，促进团队合作，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，并定量评估结构对电荷分布，热力学，以及分离过程和电化学反应中的反应机理。溶剂化结构和反应状态的二氧化碳模型化合物内和在HBOC电解质-电极界面将通过光谱学，中子和X射线反射率，和电分析技术进行研究。这些研究将为理解小分子在复杂溶剂中的结构和行为动力学提供基础。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？以及（2）界面结构对电子和质子转移以及二氧化碳还原机理的选择性有何影响？从这项研究的结果将有助于理解的HBOC电解质的双电层结构，因为它们不能被解释的传统模型适用于稀体系。这些结果也将影响电解质在二氧化碳共催化中的作用的讨论。该项目将在本科和研究生课程以及公共宣传中应用STEM教育理念“通过绘画和艺术插图学习”。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，以及促进艺术和工程学生之间的跨学科交流。该奖项反映了NSF的法定使命，并通过使用基金会的智力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.