(357ai) Development of Tandem Systems for Carbon Dioxide and Carbon Monoxide Electroreduction

While my thesis work has been predominately focused on carbon dioxide (CO₂) and carbon monoxide (CO) electrolysis, the scope of my research interests is not limited to those specific chemistries. My interests more broadly relate to reaction chemistry. I have experience working with thermal and electrochemical catalysis in reactor design, reactor scale-up, and catalyst design and engineering. I am interested in working in hydrogen chemistry, CO₂ chemistry, and light alkane or biomass upgrading. Additionally, I have experience with biological processes, specifically in the downstream separation and conversion of biological materials to more valuable products. My goal is to work in the field of reactors and catalysis, but I am open to working on a variety of different chemistries and catalytic routes.

Thesis Work:

The electrochemical conversion of carbon dioxide (CO₂) to value-added products is a developing approach to offset CO₂ emissions. Previous research has driven ambient temperature electroreduction of CO₂ to single carbon products, such as carbon monoxide (CO) and formate, to technology readiness levels > 4. Higher value multi-carbon (C₂₊) products, such as ethylene and acetic acid, still suffer from low durability, low sustainability, and high energy demand when produced via direct CO₂ electroreduction. Therefore, an alternative to direct CO₂ reduction is to undergo tandem CO₂-to-CO and CO-to-C₂₊ electroreduction. Tandem systems have been shown to have higher selectivity towards single products, specifically acetate, and improved conversion of CO₂-to-C₂₊ products. This presentation will focus on my thesis work related to developing and scaling tandem CO₂ electrolysis. My initial research efforts focused on producing a small-scale system to produce acetate from CO₂ for food growth. Through reactor and system design of a tandem CO₂-to-CO-to-acetate process, acetate was produced at greatly improved selectivities and single-pass CO₂ conversion compared to direct CO₂ electrolysis. Additionally, the acetate was effectively utilized by various edible organisms such as algae, yeast, and mushrooms at efficiencies greater than natural photosynthesis. Building from this work, a thorough investigation was done into the CO electrolyzer. The primary goal was to generate acetate at concentrations more reasonable for downstream separation. It was discovered that certain anodes were not only non-reactive with acetate but also could partially oxidize by-products towards the acetate, creating a highly pure product stream. As a result, acetate was produced from CO at >50 wt% and purities exceeding 99%. This work has led to my most recent projects that focus on scaling the tandem systems to power inputs approaching 1 kW. Many aspects of standard lab-scale (~ 3kW) reactors need to be reconsidered when scaling to higher power input systems. Things taken for granted on a small scale, such as flow pattern design, gas/liquid feed patterns, membrane, and electrodes, had to be redesigned. Knowledge gained from the development of this stack system will allow for accelerated future development of tandem CO₂ electroreduction at pilot and industrial scales.