Exsolved metallic iron nanoparticles in perovskite cathode to enhance CO2 electrolysis

Traditional metal and metal cermet cathodes are easy to be oxidized when operating with pure CO2 electrolysis, which therefore leads the degradation of electrolysis performance. Redox stable ceramic cathode provides alternative to achieve direct electrolysis of CO2; however, they show very limited catalytic activity toward CO2 splitting. In this work, we prepare perovskite materials La0.75Sr0.25Cr0.5Fe0.5+xO3−δ (LSCrFx, x = 0–0.1) through synergistic doping and treat them in H2/Ar to exsolve metallic Fe nanoparticles on LSCF scaffolds to enhance the catalytic activity. With the exsolution of iron nanoparticles, the cathode performance is enhanced by ~ 4–5 times with the CO product of 5.88 mL min−1 cm−2 and the current efficiency of ~ 97.5%. We further demonstrate the excellent thermal stability of CO2 electrolysis even after a continuous operation of 60 h and 6 redox cycles. This inspires exsolving metal nanoparticles over perovskite surface as a new technology for simultaneously enhancing catalytic activity and stability.