STTR Phase I: Scalable CO2 electrolyzers for the production of ethylene glycol and chlorine

The broader impact/commercial potential of this STTR project is the technical and economic demonstration of a device for the the polymer chemical industry. Ethylene glycol is primarily used in the production of plastics for textiles and food packaging. Chlorine is a major industrial chemical used in water purification and fabrication of polyvinyl chloride (PVC) fabrication. This proposed electrochemical process utilizes waste carbon dioxide and renewable electricity, resulting in net carbon-negative emissions, unlike petrochemical sourcing. Combining ethylene glycol and the co-production of chlorine will make the overall process cost-competitive with production from fossil feedstocks, while supporting environmental sustainability. This platform technology holds promise for an extension to other parts of the chemical industry. This STTR Phase I project proposes to address the sustainable co-production of three major chemicals by one unitized device: Chlorine (Cl2), sodium hydroxide (NaOH), and ethylene glycol from renewable electricity, brine, and carbon dioxide. Current carbon dioxide reduction (CO2RR) suffers from three major constraints: 1) high electricity costs, 2) low relative price of bulk chemicals, and 3) low energy efficiency of CO2 reduction. This project will address these constraints by using recently developed energy efficient CO2RR to ethylene glycol catalysts and co-producing Cl2 and NaOH to offset the electricity cost and low ethylene glycol price. Three technical barriers that result from combing Cl2, NaOH, and CO2RR will be addressed: A) Producing Cl2 and NaOH, which requires strict product separation (leading to less valuable hypochlorite and impure NaOH); B) Maintaining three different pH conditions in the cell (acidic for chlorine, basic for alkali, and neutral for CO2RR); and C) Providing fundamental insights into the membrane, electrode, and electrolyzer designs for complex multiproduct processes. These will be addressed by combined experiments and modeling. 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.