Abstract
CO2 emissions are a significant environmental problem which has garnered global interest from both the scientific and political community. One method to reduce emissions is to capture CO2 and convert it to useful products, such as chemical feed-stocks. A method to achieve this is via co-electrolysis of CO2 and H2O, using a high temperature solid oxide cell, to produce synthesis gas – an important intermediate to the production of synthetic liquid fuels.
The potential to convert CO2 into synthetic fuel forms a major pathway for global CO2 utilization and could address the issues of depleting fossil fuel reserves and global warming, however, the reaction mechanisms occurring during cell operation for a co-electrolysis system are currently not well understood. This information is necessary to improve performance by engineering materials and operating conditions which are ideal for high gas conversion rates and long term cell performance. Previous studies have suggested that carbonate species may be an important intermediate to CO2 reduction during electrolysis and shows dependencies with temperature and applied potential.[1] This study investigates the electrochemical impedance of electrolysis cells to determine potential rate limiting mechanisms occurring during cell operation. Results correlating cell performance to surface species detected in-situ using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) obtained under varying fuel and temperature conditions will be discussed.
[1] D.J. Cumming, C. Tumilson, R. Taylor, S. Chansai, A.V. Call, J. Jacquemin, C. Hardacre, R.H. Elder,
Faraday Discuss., 2015, 182, 97-111