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An Experimental- and Simulation-Based Evaluation on the CO_2 Utilization Efficiency in Aqueous-based Electrochemical CO_2 Reduction Reactors with Ion-Selective Membranes

Lin, Meng and Han, Lihao and Singh, Meenesh R. and Xiang, Chengxiang (2019) An Experimental- and Simulation-Based Evaluation on the CO_2 Utilization Efficiency in Aqueous-based Electrochemical CO_2 Reduction Reactors with Ion-Selective Membranes. ACS Applied Energy Materials, 2 (8). pp. 5843-5850. ISSN 2574-0962. doi:10.1021/acsaem.9b00986.

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The CO_2 utilization efficiency of three types of electrochemical CO2 reduction (CO_2R) reactors using different ion-selective membranes, including anion exchange membrane (AEM), cation exchange membrane (CEM), and bipolar membrane (BPM), was studied quantitively via both experimental and simulation methods. The operating current density of the CO_2R reactors was chosen to be between 10 – 50 mA cm^(-2) to be relevant for solar-fuel devices with relatively low photon flux from sunlight. In the AEM based CO_2R reactor with a 6-electron per carbon CO_2R at the cathode surface, an upper limit of 14.4% for the CO_2 utilization efficiency was revealed by modeling and validated by experimental measurements in CO_2 saturated aqueous electrolytes without any buffer electrolyte. Improvements in CO_2 utilization efficiency were observed when additional buffer electrolyte was added into the aqueous solution, especially in solutions with low bicarbonate concentrations. The effects of the feed rate of the input CO_2 stream, the Faradaic Efficiency (FE) and the participating electron numbers of the cathode reaction on the CO_2 utilization efficiency was also studied in the AEM based CO_2R reactor. The CEM based CO_2R reactor exhibited low CO_2 utilization efficiency with re-circulation between the catholyte and the anolyte, and was unsustainable due to the cation depletion from the anolyte without any re-circulation. The BPM based CO_2R reactor operated continuously without a significant increase in the cell voltage and exhibited significantly higher CO_2 utilization efficiency, up to 61.4%, as compared to the AEM based CO_2R reactors. Diffusive CO_2 loss across the BPM resulted in relatively low CO_2 utilization efficiency at low operating current densities. Modeling and simulation also provided target BPM properties for higher CO_2 utilization efficiency and efficient cell operation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Lin, Meng0000-0001-7785-749X
Han, Lihao0000-0002-0452-3381
Singh, Meenesh R.0000-0002-3638-8866
Xiang, Chengxiang0000-0002-1698-6754
Alternate Title:An Experimental- and Simulation-Based Evaluation on the CO2 Utilization Efficiency in Aqueous-based Electrochemical CO2 Reduction Reactors with Ion-Selective Membranes
Additional Information:© 2019 American Chemical Society. Received: May 17, 2019; Accepted: June 27, 2019; Published: June 27, 2019. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award DE-SC0004993, in collaboration with the Materials and Systems Engineering Laboratory at the University of Illinois at Chicago. Meng Lin acknowledges support from the Swiss National Science Foundation through the Early Postdoc Mobility Fellowship, Grant P2ELP2_178290. M.R.S. acknowledges the support from the Department of Chemical Engineering at the University of Illinois at Chicago. Author Contributions: M.L. and L.H. contributed equally to this work. The authors declare no competing financial interest.
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Swiss National Science Foundation (SNSF)P2ELP2_178290
University of Illinois, ChicagoUNSPECIFIED
Subject Keywords:electrochemical CO_2 reduction, CO_2 utilization efficiency, ion-exchange membrane, modeling, ionic conductivity, bipolar membrane
Issue or Number:8
Record Number:CaltechAUTHORS:20190627-130708138
Persistent URL:
Official Citation:An Experimental- and Simulation-Based Evaluation of the CO2 Utilization Efficiency of Aqueous-Based Electrochemical CO2 Reduction Reactors with Ion-Selective Membranes. Meng Lin, Lihao Han, Meenesh R. Singh, and Chengxiang Xiang. ACS Applied Energy Materials 2019 2 (8), 5843-5850 DOI: 10.1021/acsaem.9b00986.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96790
Deposited By: George Porter
Deposited On:27 Jun 2019 20:27
Last Modified:16 Nov 2021 17:23

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