Highly efficient CO2 electrolysis to CO on Ruddlesden–Popper perovskite oxide with in situ exsolved Fe nanoparticles

Abstract

We prepared a highly active and stable cathode catalyst for a solid oxide electrolysis cell (SOEC), decorated with in situ exsolved Fe nanoparticles (NPs) socketed on La_1.2Sr_0.8Mn_0.4Fe_0.6O_4−α (R.P.LSMF), toward the CO₂ electrolysis reaction to produce CO selectively. This catalyst was derived from the perovskite structure of La_0.6Sr_0.4Mn_0.2Fe_0.8O_3−δ (LSMF) by simple annealing in a H₂ atmosphere and showed high current densities of 2.04, 1.43, and 0.884 A cm⁻² at 850, 800, and 750 °C, respectively, at a voltage of 1.5 V with corresponding total polarization resistance values of 0.205, 0.326, and 0.587 Ω cm², respectively, at an open circuit voltage. The highly improved performance should be ascribed to the in situ exsolved Fe NPs anchored on Ruddlesden–Popper oxide and to the increased contents of oxygen vacancies in R.P.LSMF. More importantly, this active catalyst also exhibited a stable voltage profile for 100 h operation at an constant current density of 1.8 A cm⁻², suggesting that the catalyst Fe–R.P.LSMF proposed in this study is a highly promising candidate for use in an efficient SOEC cathode for CO₂ electrolysis processes.