Electrochemical Performance of La_0.43Ca_0.37Ti_0.94Ni_0.06O_3−δ Surface Decorated with Different CeO₂ Contents as Reversible Solid Oxide Cell (RSOC) Fuel Electrodes

Development of fuel electrodes for reversible solid oxide cells (RSOCs) is important for achieving good performance and stability under both solid oxide fuel cell and electrolysis cell operation modes. In this work, CeO2-decorated La0.43Ca0.37Ti0.94Ni0.06O3−δ (denoted as LCTN-Ce) fuel electrodes were prepared via a simple hydrothermal route, where CeO2 is uniformly decorated onto the external surface of the LCTN-Ce electrode with in situ exsolved Ni nanoparticles (NPs) after reduction treatment. The decorated CeO2 content can be regulated by adjusting the hydrothermal treatment time and precursor solution concentration. As the decorated CeO2 content increases from 0.81 to 2.05%, the conductivity of the LCTN-Ce electrode decreases while the oxygen vacancy concentration increases, comprehensively affecting the cell power output and CO2 electrolysis activity. The electrolyte-supported cell assembled with LCTN-1.46Ce cell with a moderate CeO2 content of 1.46% shows an excellent reversible electrochemical performance and RSOC stability in 50% H2/50% CO2 at 750 °C. The hydrothermal decoration provides a facile way to modify perovskite oxides, and the LCTN-Ce with in situ exsolved Ni NPs and surface-decorated CeO2 is proved to be a potential RSOC fuel electrode material.