CAREER: Novel redox-active electrolyte additives to enhance efficiency and direct product selectivity in electroreduction reactions

摘要：题目：职业：新型氧化还原活性电解质添加剂，以提高电还原反应的效率和直接产物选择性提案1653430:McCloskey， Bryan该项目将在电化学工程领域产生基础知识，这对许多能量转换和存储技术至关重要。该项目将在两个目标应用中推进电化学还原反应的知识。第一种是用于交通运输的锂- o2电池（通常称为锂-空气电池）。这种电池的化学性质保证了汽车推进所需的高能量和功率密度。第二个应用是二氧化碳的电化学还原，这是一种将二氧化碳隔离或再利用并将其转化为更高价值的燃料或化学品的方法。这两种应用都需要更多的基础知识，了解潜在的电化学还原反应是如何在设备内工作的，无论是电池还是二氧化碳转换设备。该项目着眼于装置中的电解质相如何与电极相互作用，在电极表面发生关键的还原化学反应。该项目着眼于可以作为电荷载体的电解质成分，以促进发生在电极表面和电解质介质界面上的关键电化学反应。这项基础研究可能为能源可持续性和减少汽车排放提供一条途径。该教育计划将利用研究和推广活动，使加州旧金山东湾地区的电化学工程研究界、研究生、本科生和大学预科生受益。PI正在通过研讨会和指导计划扩大本科生的研究经验。为了填补现有电化学工程教育资源的空白，我们将构建一系列在线视频模块，向对电化学感兴趣的科学家和学生教授基本概念。外展活动还将继续向东湾社区代表性不足的小学生教授简单的电化学概念。本研究的总体目标是通过将适当选择的氧化还原活性分子（氧化还原介质）掺入电解质中，提高重要电化学还原反应的效率和选择性，特别是O2和CO2还原反应。氧化还原介质是进行可逆电荷转移反应的分子，其中正向反应描述还原反应，反向反应描述氧化反应。PI在初步工作中表明，通过在电解质中加入氧化还原活性分子，可以有效地控制非水氧还原反应机理。使用这种方法可以提高选择性和能量效率，尽管潜在的机制尚不清楚，可能与溶液中O2、还原氧中间体、电子、氧化还原介质和离子之间的相互作用有关。该项目还将研究二氧化碳的电化学还原反应，特别是形成燃料或化学品的多碳产品。氧化还原介质的使用为CO2还原反应的研究开辟了一条全新的途径。该项目将研究电子/离子向O2/CO2的转移，并采用选定的氧化还原分子，这些氧化还原分子将影响O2和CO2还原反应的机制，从而为提高产物的选择性和效率提供途径。该项目的任务将利用独特的定量实验能力，包括产品分布的定量分析、差分电化学质谱分析、在线电化学气相色谱分析和核磁共振光谱分析。PI将确定有用的氧化还原活性分子类别，这些分子可以改变电荷向O2和CO2转移的机制，从而为改善每个系统中理想的产物形成选择性和能量效率提供途径。

Public Abstract:Title: CAREER: Novel redox-active electrolyte additives to enhance efficiency and direct product selectivity in electroreduction reactionsProposal 1653430: McCloskey, Bryan This project will generate fundamental knowledge in the field of electrochemical engineering that is critical to a number of energy conversion and storage technologies. The project will advance knowledge in electrochemical reduction reactions for two targeted applications. The first is a Lithium-O2 battery (commonly called a lithium-air) for transportation applications. This battery chemistry promises high energy and power density that would be required for propulsion in an automobile. The second application is for CO2 electrochemical reduction, a method to sequester or reuse CO2 and convert it into a higher valued fuel or chemical. Both of these applications share the need for more fundamental knowledge on how the underlying electrochemical reduction reactions work within the device, whether a battery or CO2 conversion device. This project looks at how the electrolyte phase in the device interacts with the electrode where the key reduction chemistry occurs on the surface of the electrode. The project looks at electrolyte components that could act as charge carriers to facilitate the key electrochemical reactions that take place at the interface of the electrode surface and the electrolyte medium. This fundamental research may provide a route to energy sustainability and reduced vehicle emissions. The educational plan will leverage research and outreach activities to benefit the electrochemical engineering research community and graduate and undergraduate and pre-college students in the East Bay Area of San Francisco, California. The PI is expanding undergraduate student research experiences with a symposium and mentoring program. To fill a gap in available electrochemical engineering educational resources, a series of online video modules will be constructed to teach fundamental concepts to scientists and students interested in electrochemistry. Outreach activities will also continue to teach simple electrochemical concepts to underrepresented elementary students in East Bay communities.The overall objective of this proposed research is to improve efficiency and selectivity of important electrochemical reduction reactions, specifically O2 and CO2 reduction, by incorporation of appropriately selected redox-active molecules (redox mediators) into the electrolyte. Redox mediators are molecules that undergo a reversible charge transfer reaction where the forward reaction describes the reduction reaction and the reverse reaction describes the oxidation reaction. The PI has shown in preliminary work that the nonaqueous oxygen reduction reaction mechanism can be beneficially manipulated through the inclusion of redox-active molecules into the electrolyte. Improved selectivity and energy efficiency has been indicated using this approach although the underlying mechanisms are unclear and could be related to interactions between O2, reduced oxygen intermediates, electrons, the redox mediator, and ions in solution. The project will also look at CO2 electrochemical reduction reactions, particularly to form multi-carbon products for fuels or chemicals. The use of redox mediators could open an entirely new avenue of research on the CO2 reduction reaction. The project will look at both electron/ion transfer to O2/CO2 and employ selected redox molecules that will impact the mechanism of the O2 and CO2 reduction reactions thereby providing a route to improved product selectivity and efficiency. The project's tasks will leverage unique quantitative experimental capabilities, including quantification of product distributions using, differential electrochemical mass spectrometry, online electrochemical gas chromatography, and nuclear magnetic resonance spectroscopy. The PI will identify useful classes of redox-active molecules that can alter the mechanism of charge transfer to O2 and CO2, thereby providing a route to improving desirable product formation selectivity and energy efficiency in each system.