A Tandem Electrolysis Process for Multi-Carbon Chemical Production from Carbon Dioxide (Final Technical Report)

Technical Report · Mon Jan 08 04:00:00 EST 2024

DOI:https://doi.org/10.2172/2280644· OSTI ID:2280644

Jiao, Feng ^[1]

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1. Univ. of Delaware, Newark, DE (United States); University of Delaware

a two-step CO₂ electroreduction process for selective production of acetate and ethylene was successfully developed at the kW-scale. The CO₂ and CO electrolyzers were first investigated individually on the Watt-scale to achieve high current densities and more durable operation by using a reinforced GDL. High CO₂ conversion was obtained in the first CO₂ electrolyzer to produce a CO-dominant gas stream with minimal CO₂, and highly pure acetate stream was produced in the second CO electrolyzer by using NiFe anode, which promoted alcohol oxidation to carboxylates. The two-step process operated stably for 200 h with acetate and ethylene as the major C₂₊ products. Degradation mechanism study revealed that the flooding and the salt formation in the GDL is likely the biggest contributor to the performance degradation for both CO₂ and CO electrolyzers. A 1,000 cm² CO electrolyzer stack was then designed, fabricated, and operated up to a total current of 300 A along with a 500 cm² CO₂ electrolyzer stack which was operated up to a total current of 100 A. The CO electrolyzer stack demonstrated good stability at 300 A for at least 125 h at a carbon selectivity >96%. The impact of CO₂, O₂, N₂, SO_x, and NO_x gas impurities on the CO electrolyzer stack was studied and a relatively high resistance to these contaminants was demonstrated. Electroreduction of CO₂ into acetic acid was also demonstrated to be environmentally favorable when compared to the traditional production of acetic acid when powered by renewable electricity. Additionally, electricity cost was identified as the primary source of cost sensitivity indicating substantial economic improvements could be achieved by continuing to drive down the cost of renewable electricity. Overall, the presented approach demonstrates the feasibility of the two-step electrochemical CO₂ reduction process for the effective production of C₂₊ products at the kW-scale which should inspire future scaling efforts accelerating commercialization.

• Research Organization: Univ. of Delaware, Newark, DE (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy and Carbon Management (FECM)
• DOE Contract Number: FE0031910
• OSTI ID: 2280644
• Report Number(s): DOE-UD--FE31910
• Country of Publication: United States
• Language: English

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