Selective Hydrocarbon Production from Carbon Dioxide Electro-reduction via Electrochemical Potential and Mass Transport Engineering

利用可再生电力将水和二氧化碳转化为能量密集的燃料和高价值的化学品，可以改善间歇性太阳能和风能的储存和利用。这种“太阳能燃料”技术在利用可再生能源和将二氧化碳中的碳隔离成用于制造聚合物等工业产品的增值化学品方面具有优势。该项目利用以二氧化碳为原料的电化学转化和外部施加的电位（电压）来生产更高价值的化学品。研究人员将研究如何设计电化学电位在该装置上的应用，以便以节能的方式提高乙烯等产品的产量。该项目将包括研究使用一系列电势脉冲的影响，而不是对发生在设备电极和电解质边界的基本反应进行稳定的应用。其目标是应用一系列电压脉冲，并改变其频率和能量大小，从而调整发生的反应，使其有利于碳氢化合物的生产，而不是一氧化碳等竞争产品。对于更广泛的教育影响，pi将继续致力于通过夏季和学年的研究项目培养本科生研究人员。pi将继续为学生和高级研究人员举办能源和材料研究人员的研究伦理研讨会。研究成果将被整合到康奈尔大学化学工程顶点课程项目中，这些项目旨在整合二氧化碳处理技术的技术创新、知识产权、实用工程、创业和交流。这些活动旨在提高学生在本科和研究生阶段对化学和材料工程的兴趣，特别是女性和代表性不足的少数民族成员，以建立未来STEM劳动力的多样性。这项研究将导致对如何通过调整应用电化学电位的时间分布来控制二氧化碳电还原反应的选择性的基本理解。包括表面吸附、双电层和输运在内的许多变量在二氧化碳电还原选择性中起重要作用。该项目的驱动假设是，该系统中的关键反应和输运现象发生在不同的时间尺度上，可以利用这些时间尺度来影响观察到的反应选择性。这个项目试图通过调整电化学电位脉冲的时间剖面来控制这些变量。重点是确定设计电化学电位的时间分布的原则，以促进烃的产生和抑制析氢反应。除了选择性控制外，电化学电位的时间控制为解决二氧化碳电还原过程中竞争途径及其速率常数的开放性问题提供了机会。光谱学和模拟将并行进行，以揭示电化学电位在时间控制期间的热力学和动力学。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 use of renewable electricity to convert water and carbon dioxide into energy-dense fuels and high-valued chemicals can improve the storage and utilization of intermittent solar and wind energy. This technology for "solar fuels" has benefits in utilization of renewable energy sources and in sequestering carbon from carbon dioxide into value added chemicals used to make industrial products such as polymers. This project utilizes an electrochemical conversion with carbon dioxide as a feedstock and an externally applied electrical potential (voltage) to produce higher valued chemicals as a goal. The researchers will investigate how to engineer the application of the electrochemical potential to the device in order to improve the yield of products such as ethylene in an energy efficient manner. The project will involve investigations of the impact of using a series of pulses of electrical potential rather than a steady application on the elementary reactions that occur at the boundary of the electrode and electrolyte of the device. The goal is that application of a series of voltage pulses and varying its frequency and energy magnitude could tune the reactions occurring to favor production of hydrocarbons over competing products such as carbon monoxide. For educational broader impacts, the PIs will continue their commitment to fostering undergraduate researchers through summer and academic year research projects. The PIs will continue to sponsor a research ethics workshop for researchers in energy and materials designed for both students and senior investigators. The research outcomes will be integrated into Cornell chemical engineering capstone course projects that are designed to integrate technological innovation, intellectual property, practical engineering, entrepreneurship, and communication in carbon dioxide processing technologies. These activities are aimed at improving students' interests in chemical and materials engineering at both undergraduate and graduate levels, especially for women and members of underrepresented minorities to build diversity in the future STEM workforce.This research will result in fundamental understanding on how to control the selectivity of the carbon dioxide electroreduction reaction by tailoring the temporal profile of the applied electrochemical potential. A number of variables including surface adsorbates, electrical double layer, and transport, play an important role in the carbon dioxide electroreduction selectivity. The project's driving hypothesis is that key reaction and transport phenomena in this system occur at varying timescales that could be taken advantage of to impact the observed reaction selectivity. This project seeks to control these variables by tuning the temporal profile of the electrochemical potential pulse. The central focus is to identify the principles for designing the temporal profile of the electrochemical potential to promote hydrocarbon production and suppress the hydrogen evolution reaction. In addition to selectivity control, the temporal control of the electrochemical potential represents an opportunity to address open questions concerning competing pathways in the carbon dioxide electroreduction and their rate constants. Spectroscopy and simulations will be done in parallel to reveal the thermodynamics and kinetics during the temporal control of the electrochemical potential.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.