Electrochemical\nPerformance of La<sub>0.43</sub>Ca<sub>0.37</sub>Ti<sub>0.94</sub>Ni<sub>0.06</sub>O<sub>3−δ</sub> Surface Decorated with\nDifferent CeO<sub>2</sub> Contents as

Development of fuel electrodes for reversible solid oxide\ncells\n(RSOCs) is important for achieving good performance and stability\nunder both solid oxide fuel cell and electrolysis cell operation modes.\nIn this work, CeO<sub>2</sub>-decorated La<sub>0.43</sub>Ca<sub>0.37</sub>Ti<sub>0.94</sub>Ni<sub>0.06</sub>O<sub>3−δ</sub> (denoted\nas LCTN-Ce) fuel electrodes were prepared via a simple hydrothermal\nroute, where CeO<sub>2</sub> is uniformly decorated onto the external\nsurface of the LCTN-Ce electrode with in situ exsolved Ni nanoparticles\n(NPs) after reduction treatment. The decorated CeO<sub>2</sub> content\ncan be regulated by adjusting the hydrothermal treatment time and\nprecursor solution concentration. As the decorated CeO<sub>2</sub> content increases from 0.81 to 2.05%, the conductivity of the LCTN-Ce\nelectrode decreases while the oxygen vacancy concentration increases,\ncomprehensively affecting the cell power output and CO<sub>2</sub> electrolysis activity. The electrolyte-supported cell assembled\nwith LCTN-1.46Ce cell with a moderate CeO<sub>2</sub> content of 1.46%\nshows an excellent reversible electrochemical performance and RSOC\nstability in 50% H<sub>2</sub>/50% CO<sub>2</sub> at 750 °C.\nThe hydrothermal decoration provides a facile way to modify perovskite\noxides, and the LCTN-Ce with in situ exsolved Ni NPs and surface-decorated\nCeO<sub>2</sub> is proved to be a potential RSOC fuel electrode material.