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可持续战略的关键一步。为了技术可行性，需要更有效和更具成本效益的ERCO2途径。特别是，ERCO2电池中电解质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，但目前还没有得到很好的理解。该项目通过采用一套先进的化学表征技术来解决这一需求，从而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。结合原位表面特异性光谱、电动力学和同位素标记技术，将在分子水平上阐明电极表面介导的ECRCO2及其与电解质中阳离子和阴离子相互作用的机制。碳酸氢盐是ECRCO2中最常用的阴离子，通过二氧化碳-碳酸氢盐的动态平衡，提高电极表面的有效二氧化碳浓度，从而提高反应速率。此外，静电结合的阳离子可以通过在负电极电位下的位点阻断来减少反应物到达表面的途径。建立有机阳离子的结构与位点阻断效应之间的关系。在这些机理研究中获得的见解将用于未来ECRCO2装置的聚合物电解质的设计。此外，设计具有最小输运限制的纳米结构催化剂的原则将通过开发一种实验方法来提取，该实验方法可以在距离电极表面10 nm的范围内测量pH值，进而测量CO2浓度。更广泛地说，将特别强调通过基于移动设备的软件平台（“绿色科技”应用程序）吸引和留住科学、技术、工程和数学（STEM）项目中代表性不足的群体的学生，以提供可持续和无害环境的能源利用需求的教育和意识。

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.