“…Therefore, it is essential to improve the catalytic activity of the cathode to enhance the cell performance. Ni-based cermets, such as Ni-GDC (Gd 2 O 3 -doped CeO 2 ) and Ni-YSZ (Y 2 O 3 -stabilized ZrO 2 ), widely used as cathodes of SOECs, have the advantages of low costs and high electrochemical activities. − However, Ni-based cathodes face various problems, such as Ni oxidation, Ni coarsening, and carbon deposition, thus threatening their long-time operation. − LaCrO 3 - and SrTiO 3 -based perovskite oxides with matching thermal expansion coefficients (TECs) to other components of SOECs were considered as potential cathodes for CO 2 electroreduction in SOECs, − while their electrochemical activity still needs to be significantly improved. − Therefore, Fe-, Co-, and Ni-based perovskite oxides were developed, such as La 0.6 Sr 0.4 Fe 0.8 Ni 0.2 O 3−δ F 0.1 , La 0.6 Sr 0.4 Co 0.5 Ni 0.2 Mn 0.3 O 3−δ , La 0.66 Ti 0.8 Fe 0.2 O 3−δ , and Sr 2 Fe 1.35 Mo 0.45 Co 0.2 O 6−δ . − In these perovskite oxides, the easily reducible metal elements (Fe, Co, and Ni) are exsolved from perovskite bulk under a H 2 -containing atmosphere or a reducing potential to form metal nanoparticles on perovskite surfaces. − The interfaces of metal nanoparticles/perovskite have been identified to be highly active toward CO 2 electroreduction because the metal nanoparticles can strengthen the adsorption of intermediates and lower the CO 2 dissociation barriers. Meanwhile, the perovskite substrate with high oxygen ionic conductivity facilitates the diffusion of oxygen ions from the metal nanoparticles/perovskite interfaces to electrolyte. − …”