(730e) Electrochemical Reduction of Carbon Dioxide By Means of Transition Metal Infiltrated Cathodes in Solid Oxide Electrolyzer Cells

Population and economic growth have led to a substantial increase in worldwide energy demand and CO₂ emissions. Although the world is transitioning towards renewable energy sources such as wind and solar, these sources will not satisfy increasing energy demand requiring continued use of fossil fuels. The continued use of fossil fuels makes development of cost-effective carbon capture, utilization, and storage technologies essential to sustainable worldwide growth. Over the past two years, Ohio University (OHIO) has been investigating conversion of carbon dioxide (CO₂) into more valuable industrial feedstocks such as carbon monoxide (CO). CO plays a significant role in various industrial applications including the production of chemical compounds as well as the production of synthetic fuels.

Commercially, CO is produced either by steam reforming of gaseous hydrocarbons or by gasification of heavy hydrocarbons (liquids and solids), where it is produced along with hydrogen (H₂) to form synthetic gas mixture (syngas) [1]. Pure CO is obtained by separating it from the syngas mixture using different techniques such as cryogenic separation, pressure swing adsorption (PSA), and membrane separation [1,2]. The aforementioned techniques are energy intensive requiring large, centralized facilities to achieve favorable economics. CO₂ electrolysis has shown to be a viable option for CO production due to its simplicity and low operating cost. High temperature CO₂ electrolysis utilizing solid oxide fuel cell (SOFC) technology offers enhanced reaction kinetics and high cell efficiencies at high temperatures, potentially offering a cost-effective modular alternative which can be integrated into industrial settings [3].

OHIO, with support from the U.S. Department of Energy [DE-FE0031709], is developing a solid oxide electrolyzer cell (SOEC) to convert CO₂ into more valuable products such as CO. In this study, SOEC cathodes were fabricated using various transition metal electrocatalysts (cobalt, copper, and nickel) infiltrated into a porous Gd_0.10Ce_0.90O_1.95 (GDC-10) scaffold, while (La_0.80Sr_0.20)_0.95MnO₃ (LSM20) was used for the anode fabrication. The electrochemical performance of the transition metal-based electrocatalysts were evaluated at different temperatures (750, 800, and 850 °C) by supplying a blend of CO₂, CO, and N₂ (81% CO₂, 10% CO, 9% N₂) on the cathode side and air on the anode side. The fabrication techniques as well as the electrochemical performance of the transition metal electrocatalysts will be discussed in this presentation.

[1] Wilbur, S.; Williams, M.; Williams, R.; Scinicariello, F.; Klotzbach, J. M.; Diamond, G. L.; Citra, M. Toxicological Profile for Carbon Monoxide. Agency for Toxic Substances and Disease Registry (ATSDR) Toxicological Profiles; Agency for Toxic Substances and Disease Registry (US): Atlanta (GA), 2012.

[2] Poudel, J.; Choi, J.; Oh, S. Process Design Characteristics of Syngas (CO/H2) Separation Using Composite Membrane. Sustainability 2019, 11 (3), 703.

[3] Ebbesen, S. D.; Mogensen, M. Electrolysis of Carbon Dioxide in Solid Oxide Electrolysis Cells. J. Power Sources 2009, 193 (1), 349–358.