Theoretical Investigation of CO2 Reduction at Ni/SDC and La(Sr)FeO3-δ Cathodes in Solid Oxide Electrolysis Cells

Abstract

Electrochemical CO2 reduction in solid oxide electrolysis cell (SOEC) is a promising technology to address the global issue of greenhouse emissions. To further advance the development of catalyst, it is necessary to gain theoretical insights into high temperature CO2 electroreduction mechanisms on perovskite La(Sr)FeO3-δ and conventional Ni/SDC using Density Functional Theory (DFT). To study the effects of interface oxygen vacancy on CO2 electrolysis on Ni/SDC, surface models with and without interface oxygen vacancy were considered. In addition, the most stable La(Sr)FeO3-δ surface model under SOEC operation conditions with 4 oxygen vacancies was also built. CO2 reduction reaction is most favorable for the strongest CO2 adsorption on Ni/SDC (111) surface, while on La0. 5Sr0. 5FeO2.75 (001) surface, this reaction is most favorable for moderate CO2 adsorption. The adsorption configurations of CO2 and CO that would make CO2 electrolysis most likely to occur were determined for each of the surface models.