Assessment of the Use of Switchable Polarity Solvents for Delivery of CO2 for Electrochemical Reduction

Wednesday, 4 October 2017: 12:00
National Harbor 8 (Gaylord National Resort and Convention Center)
L. A. Diaz, B. Adhikari, T. E. Lister, A. D. Wilson, and E. J. Dufek (Idaho National Laboratory)
Biomass conversion is a rising alternative to substitute fuels, chemicals and other products currently obtained from fossil sources. However, biomass conversion technologies such as pyrolysis suffer from low carbon-to-fuel efficiency (38-47%), with the remainder of the carbon ultimately ending up forming CO2 and resulting in biogenic green-house gas (GHG) emissions [1]. An alternative to decrease the CO2 emission from biomass conversion, and contribute to the sustainability of the biomass processing, is the capture and conversion of CO2 to beneficial products such as chemicals and fuels via renewable electricity.

Aqueous electrochemical reduction of CO2 has been of growing interest as a solution for GHG mitigation and due to the high diversity of products that can be selectively obtained depending on the electrocatalyst used (e.g. alcohols, hydrocarbons, CO etc.) [2]. However, three main technical problems have been identified for the process feasibility: 1) low solubility of CO2 in aqueous media hinders mass transport, 2) high reaction overpotentials, and 3) obtaining a quality concentrated CO2 feedstock [3,4]

In this work, switchable polarity solvents (SPS) are used to capture and increase the CO2 concentration in aqueous media. SPS are emerging as an extremely versatile class of materials which shift polarity and solubility upon being exposed to a chemical agent, namely CO2 with water [5]. Insoluble tertiary amines react with CO2 to form soluble ions [HNR3+] and bicarbonate [6]. Hence, an ion exchange membrane assembly can be used to generate a localized acidic environment on the surface of the cathode electro-catalyst releasing CO2 for reduction.

Results of electrochemical analysis performed on metal supported catalysts will be presented




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