Theoretical Investigation of CO_2 Reduction at Ni/SDC and La(Sr)FeO_(3-δ) Cathodes in Solid Oxide Electrolysis Cells

摘要

Electrochemical CO_2 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 CO_2 electroreduction mechanisms on perovskite La(Sr)FeO_(3-δ) and conventional Ni/SDC using Density Functional Theory (DFT). To study the effects of interface oxygen vacancy on CO_2 electrolysis on Ni/SDC, surface models with and without interface oxygen vacancy were considered. In addition, the most stable La(Sr)FeO_(3-δ) surface model under SOEC operation conditions with 4 oxygen vacancies was also built. CO_2 reduction reaction is most favorable for the strongest CO_2 adsorption on Ni/SDC (111) surface, while on La_(0.5)Sr_(0.5)FeO_(2.75) (001) surface, this reaction is most favorable for moderate CO_2 adsorption. The adsorption configurations of CO_2 and CO that would make CO_2 electrolysis most likely to occur were determined for each of the surface models.