In situ exsolution of ceria nanoparticles in perovskite cathode for elevating CO2 reduction performance of solid oxide electrolysis cells (SOECs).

[Display omitted] • Performance comparison of LSCT-based cathode materials for CO 2 reduction in SOEC. • Exsolution of Ceria nanospheres enhances the electrocatalytic activity. • DRT analysis is conducted to distinguish a series of reaction processes in SOEC. • LSCT-based materials are established as electro-catalysts for CO 2 reduction. • Experimental data is simulated with an electrochemical model. The CO 2 electrochemical reduction process has been executed utilizing a solid oxide electrolysis cell, incorporating advanced cathode materials: A-site deficient calcium-doped lanthanum strontium titanate (La 0.2 Sr 0.25 Ca 0.45 TiO 3-δ , LSCT) and cerium (5 mol%)-doped lanthanum strontium calcium titanate (Ce 0.05 La 0.2 Sr 0.2 Ca 0.45 TiO 3-δ , Ce-LSCT). In both electrochemical setups, La 0.8 Sr 0.2 MnO 3-δ (LSM) and yttria-stabilized zirconia (YSZ) were employed as the anode and electrolyte, respectively. The electrocatalytic efficacy of LSCT was notably enhanced in a hydrogen-rich environment, evidenced by a reduction in cathode polarization resistance from 36.7 to 10.43 Ω.cm2, concurrent with an increase in H 2 concentration from 30 % to 50 %. Additionally, the replacement of 5 mol% strontium with cerium in the LSCT cathode composition resulted in a further decrease of polarization resistance to 4.88 Ω.cm2 at a CO 2 /H 2 molar ratio of 50/50. In a reductive atmosphere, Ceria (CeO 2) nanospheres were observed to exsolve from their lattice sites within the Ce-LSCT cathode, as verified through FE-SEM and HR-TEM analyses. These in-situ exsolved CeO 2 nanoparticles actively contributed to the electrocatalytic CO 2 reduction, achieving a superior current density of 1.01 A/cm2, surpassing the 0.69 A/cm2 recorded for the LSCT cathode. This was observed at an operational voltage of 2.5 V and a temperature of 800 °C. These outcomes suggest the potential of LSCT as a cathode material in CO 2 reduction reactions, with Ce-doping offering a pathway to further augment its electrocatalytic capabilities. [ABSTRACT FROM AUTHOR]