• Yarema, Genevieve
• Whitten, Ariel
• Freire, Maikon
• Tezel, Elif
• Denecke, Reinhard
• Guo, Dezhou
• Nikolla, Eranda

Abstract

<jats:p>Solid oxide electrolysis cells (SOECs) are promising for the selective electrochemical conversion of CO<jats:sub>2</jats:sub>, or mixed streams of CO<jats:sub>2</jats:sub> and H<jats:sub>2</jats:sub>O, into high energy products such as CO and H<jats:sub>2</jats:sub>. However, these systems are limited by the poor redox stability of the state-of-the-art Ni-based cathode electrocatalysts. Due to their favorable redox properties, mixed ionic-electronic conducting (MIEC) oxides have been considered as promising alternatives. However, improvement of the electrochemical performance of MIEC-based SOEC electrocatalysts is needed and requires an understanding of the factors that govern their activity. Herein, we investigate the effect of B-site 3<jats:italic>d</jats:italic> metal cations (Cr, Fe, Co, Ni) of LaBO<jats:sub>3</jats:sub> perovskites on their CO<jats:sub>2</jats:sub> electrochemical reduction activity in SOECs. We find that their electrochemical performance is highly dependent on the nature of the B-site cation and trends as LaFeO<jats:sub>3</jats:sub> &gt; LaCoO<jats:sub>3</jats:sub> &gt; LaNiO<jats:sub>3</jats:sub> &gt; LaCrO<jats:sub>3</jats:sub>. Among these perovskites, LaNiO<jats:sub>3</jats:sub> is the least stable and decomposes under electrochemical conditions. <jats:italic>In situ </jats:italic> characterization and <jats:italic>ab initio</jats:italic> theoretical calculations suggest that both the nature of the B-site cation and the presence of oxygen surface vacancies impact the energetics of CO<jats:sub>2</jats:sub> adsorption and reduction. These studies provide fundamental insights critical toward devising ways to improve the performance of MIEC-based SOEC cathodes for CO<jats:sub>2</jats:sub> electroreduction.</jats:p>

Topics

• perovskite
• impedance spectroscopy
• surface
• Oxygen