The　catalytic　reduction　of　CO2　to　CO　using　solid　oxide　electrolytic　cells　(SOECs)　is　considered　as　a　sustainable　solution　to　simultaneously　remove　excessive　CO2　in　the　air　and　creates　valuable　chemicals.　It　is　well　known　that　catalyst　interface　plays　an　important　role　in　heterogeneous　catalytic　process.　However,　supported　perovskite　nanoparticles　catalysts　are　still　far　away　from　satisfactory　for　industrial　application.　In　this　study,　we　prepare　a　series　of　double-layer　perovskite　materials　Sr2Fe1.5+xMo0.5O6-δ　(SF1.5+xM,　x　=　0–0.1)　through　synergistic　doping　and　pretreating　for　forming　Fe/Sr2Fe1.5+xMo0.5O6-δ　interface　to　enhance　the　catalytic　activity.　In　addition,　the　well-constructed　interface　contributes　to　an　extremely　high　current　efficiency　of　~　92.6%　at　1.4 V,　850 °C.　The　CO　yield　of　Fe/SF1.5+xM　with　this　well-developed　interface　is　as　high　as　4.6 mL min−1 cm−2,　which　was　two　times　more　than　that　of　SF1.5 M.　We　further　demonstrate　long-term　stability　of　CO2　electrolysis　even　after　a　continuous　operation　of　100 h　without　carbon　deposition.　This　inspires　establishing　well-contacted　interface　through　exsolving　metallic　nanoparticles　(NPs)　over　perovskite　material　for　significantly　improving　catalytic　activity　and　stability.　©　2022,　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.