Interplay of Mass Transport and Chemical Kinetics in the Electroreduction CO2

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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.