Interplay of Mass Transport and Chemical Kinetics in the Electroreduction CO2

二氧化碳（CO2）的电化学还原是一种碳循环或碳再利用的方式，代表了能源和环境可持续性的有前途的解决方案。尽管可再生能源的储存和碳氢化合物化学品和燃料的可持续生产具有巨大潜力，但由于缺乏有效的电催化剂，CO2的电还原受到挑战。催化剂的表面结构和通过纳米结构电极的质量传递在CO2还原为更高阶碳产物中起重要作用。本研究将通过整合实验和模拟研究，对CO2电还原过程中物质传递和化学动力学之间的相互作用有基本的了解。该项目还将促进下一代工程师的成长，以应对能源和环境可持续性方面的全球挑战。这将通过培养具有最先进的实验和理论技能的研究生，发展他们独立的研究理念，为本科生和高中生提供科学和工程研究前沿的实践经验，教育和指导K-12名来自不同背景的学生考虑在STEM领域的职业生涯。这个基础工程科学项目将促进对CO2电解过程中的传质和化学动力学。该项目通过以下努力整合了实验和计算研究：i）由在2D Cu网上生长的高密度铜（Cu）纳米线组成的模型高表面积催化剂的合成和表征; ii）使用在不同反应条件下制备的具有不同纳米尺度和表面结构的Cu纳米线进行系统的电催化研究; iii）Cu纳米线的表面结构和性质的表征研究，以了解结构对化学动力学的影响;以及iv）考虑扩散的传输建模，迁移和反应消耗的化学物种通过铜纳米线，以了解质量传递的影响，高表面积电极的电催化性能。该项目的预期成果将通过将Cu电催化剂的纳米结构与其催化性能相关联来缩小知识差距。质量输运建模工作强调了理解空间结构依赖的质量输运和表面结构依赖的化学动力学的重要性。 在这项研究中发展的基本认识将作为进一步开发先进电催化剂的指导方针，以提高CO2电解槽的能源效率、功率性能和产品选择性。该奖项反映了NSF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。

Electrochemical reduction of carbon dioxide (CO2), a way of carbon recycling or carbon reuse, represents a promising solution for energy and environmental sustainability. Despite the great potential for storage of renewable energy and sustainable production of hydrocarbon chemicals and fuels, the electroreduction of CO2 is challenged by the lack of efficient electrocatalysts. Both the surface structure of the catalysts and mass transport through the nanostructured electrodes play important roles in CO2 reduction to higher order carbon products. This research will develop fundamental understanding of the interplay between mass transport and chemical kinetics in the electroreduction of CO2 by integrating experimental and simulation studies. The project will also foster the growth of the next generation of engineers to address global challenges in energy and environmental sustainability. This will be achieved by training graduate students with state-of-the-art experimental and theoretical skills and developing their independent research philosophy, providing undergraduate and high-school students with hands-on experiences at the cutting-edge of science and engineering research, and educating and mentoring K-12 students from diverse backgrounds to consider careers in STEM fields.This fundamental engineering science project will advance the mechanistic understanding of the mass transport and chemical kinetics in CO2 electrolysis. This project integrates experimental and computational studies through the following efforts: i) synthesis and characterization of a model high surface area catalyst consisting of highly dense copper (Cu) nanowires grown on 2D Cu mesh; ii) systematic electrocatalytic studies using Cu nanowires prepared under different reaction conditions and with distinct nanoscale and surface structures; iii) characterization studies of the surface structures and properties of the Cu nanowires to understand the structure effect on the chemical kinetics; and iv) transport modeling that takes into account the diffusion, migration and reaction consumption of chemical species through the Cu nanowires to understand the mass transfer effects on the electrocatalytic performance of high-surface-area electrodes. The expected outcomes of this project will reduce the knowledge gap by correlating the nanostructures of Cu electrocatalysts to their catalytic performances. The mass transport modelling effort emphasizes the importance of understanding both spatial architecture-dependent mass transport and surface-structure dependent chemical kinetics. The fundamental understanding to be developed in this research serves as guidelines for the further development of advanced electrocatalysts toward improved energy efficiency, power performance and product selectivity of CO2 electrolyzers.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.