CAREER:Elucidating Molecular Level Interplay Between Catalysts and Electrolytes in Electrochemical Reduction of CO2

该项目致力于电化学减少温室气体二氧化碳(ERCO2)--这是生产燃料和商品化学品的可持续战略的关键一步。为了技术上的可行性，需要更有效和更具成本效益的二氧化碳排放途径。特别是，ERCO2电池中电解液和电催化剂之间的相互作用在很大程度上决定了系统的整体性能，但人们对此尚不清楚。该项目通过采用一套先进的化学表征技术来满足这一需求，以深入了解更有效的聚合物电解质和纳米结构催化剂的设计。该项目还将提高教育和公众对将二氧化碳转化为燃料和化学品的电化学过程的经济和环境影响的认识。结合原位表面特定光谱、电动和同位素标记技术，将在分子水平上阐明电极表面介导的ECRCO2的机理及其与电解液中的阳离子和阴离子的相互作用。碳酸氢盐是ECRCO2中最常用的阴离子，它通过二氧化碳-碳酸氢盐的动态平衡来提高电极表面的有效二氧化碳浓度，从而提高反应速度。此外，静电结合的阳离子可以通过负电极上的位置阻塞来减少反应物对表面的访问。有机阳离子的结构与位置封闭效应之间的关联将被建立。在这些机理研究中获得的见解将被用于未来ECRCO2装置的聚合物电解质的设计。此外，通过开发一种实验方法来现场测量电极表面10 nm范围内的pH，进而测量CO2浓度，将提取具有最小传输限制的纳米结构催化剂的设计原则。更广泛地说，将特别重视通过基于移动设备的软件平台(“GreenTech”应用程序)吸引和留住科学、技术、工程和数学(STEM)专业中代表性不足群体的学生，以提供教育和对可持续和环境友好的能源利用必要性的认识。

The project addresses electrochemical reduction of the greenhouse gas carbon dioxide (ERCO2) - a critical step in sustainable strategies for generating fuels and commodity chemicals. More efficient and cost-effective routes for ERCO2 are needed for technological viability. In particular, interactions between the electrolyte and the electrocatalyst in ERCO2 cells are largely responsible for the overall performance of the system, yet are not well understood. The project addresses this need by employing a suite of advanced chemical characterization techniques to gain insight for the design of more effective polymer electrolytes and nanostructured catalysts. The project will also increase education and public awareness of the economic and environmental impact of electrochemical processes for converting CO2 to fuels and chemicals.A combination of in-situ surface-specific spectroscopic, electrokinetic, and isotope labeling techniques will be employed to elucidate the mechanism of the electrode surface-mediated ECRCO2 and its interplay with cations and anions in the electrolyte at the molecular level. Bicarbonate, the most commonly used anion in ECRCO2, is proposed to enhance the reaction rate by increasing the effective CO2 concentration at the electrode surface via the dynamic CO2-bicarbonate equilibrium. Moreover, electrostatically bound cations could reduce the access of reactants to the surface via site blocking at negative electrode potentials. Correlation between the structure of organic cations and the site blocking effect will be established. Insights gained in these mechanistic studies will be used in the design of polymer electrolytes for future ECRCO2 devices. Further, design principles for nanostructured catalysts with minimum transport limitation will be extracted by developing an experimental method to measure the pH, and in turn CO2 concentration, within 10 nm from the electrode surface in-situ. More broadly, special emphasis will be paid to attracting and retaining students from underrepresented groups in science, technology, engineering and mathematics (STEM) programs via a mobile device based software platform (the "GreenTech" app) to provide education and awareness of the need for sustainable and environmentally benign energy utilization.