An active and robust La0.75Sr0.25Cr0.5Mn0.5O3-based fuel electrode coated with in situ grown nanoparticles via electron conduction and oxygen exchange enhancements for solid oxide electrolysis cells

Abstract

Solid oxide electrolysis cells (SOECs) can afford renewable electricity storage and realize the conversion of CO₂ into valuable chemicals, but the high-temperature operating environment necessitates the advancement of efficient and durable catalysts. La_0.75Sr_0.25Cr_0.5Mn_0.5O₃ (LSCM) is recognized as a promising SOEC fuel electrode material due to its excellent redox stability and CO₂ electrolysis durability but suffers from insufficient catalytic activity. La_0.75Sr_0.2Ca_0.05Cr_0.5Mn_0.5O₃ (LSCCM) was found to yield an improved electrochemical performance via Ca doping in our previous study and is anticipated to be further optimized. Herein, in order to enlarge the active boundaries for CO₂ adsorption and conversion, the nanosized LaCo_0.6Ni_0.4O_3−δ (LCN) catalyst is in situ formed on the stable LSCCM-GDC (Gd doped CeO₂) composite layer surface via a vacuum infiltration method. The addition of LCN reduces the electrode polarization resistance by 69% in a CO₂ atmosphere at OCV, 800 °C. The electrolyte-supported single cell with the LCN/LSCCM-GDC fuel electrode achieves over a 103% increase in electrolysis current density compared to that with the bare LSCCM-GDC at 800 °C and 1.6 V. The significant improvement can be ascribed to the enhanced chemical adsorption of CO₂, increased conductivity and oxygen surface exchange after LCN surface modification. In addition, a robust operation for CO₂ reduction is obtained due to the stable skeleton structure as well as the synergistic effect of multiple components of the fuel electrode. This study not only strengthens the modification of the LCN nanoparticle catalyst towards LSCM-based fuel electrodes, but also offers an effective avenue for constructing strong-binding active interfaces with multiple transmission channels for material optimization.