Enhancing the catalytic activity and CO2 chemisorption ability of the perovskite cathode for soild oxide electrolysis cell through in situ Fe-Sn alloy nanoparticles

•Fe-Sn nanoparticles were formed through in-situ exsolution in the Sr1.95Fe1.4Sn0.1Mo0.5O6-δ perovskite.•The CO2 adsorption capacity and electrocatalytic activity are significately enhanced by Fe-Sn nanoparticles.•The single cell furnished excellent CO2 electrolysis performance, and the maximum current density of 3.269 A cm−2 at 1.8 V and 800 °C was achieved.