Robust and efficient Fe/Mn bimetal doped Pr4/3Ba2/3Co2/3Fe2/3Mn2/3O5+& delta; double perovskite catalysts for direct CO2 electrolysis

Abstract

Solid oxide electrochemical cells (SOCs) hold great promise as highly efficient energy conversion devices for the electrochemical reduction of CO2 into valuable fuels. However, the practical application of SOCs for CO2 reduction is significantly hampered by the sluggish reaction kinetics and poor stability of the fuel electrodes. Here, we report on a novel Pr4/3Ba2/3Co2/3Fe2/3Mn2/3O5+& delta; (PBCFM) with a double perovskite structure, which is highly active and durable for electrochemical reactions of H2 oxidation and CO2 reduction. Co-doping of Fe and Mn into the B-site of PrBaCo2O5+& delta; improved its structural stability, thereby preventing Ba segregation and carbonate formation under pure CO2 atmospheres and enabling the exsolution of CoFe alloy without phase decomposition. The SOC with the PBCFM electrode exhibited superior performance of 2.04 W cm-2 in peak power density in the fuel cell mode with H2 and a current density of 3.76 A cm-2 at 1.5 V in the CO2 electrolysis cell mode at 850 degrees C. Furthermore, the PBCFM electrode exhibited excellent long-term durability without any carbon coking or degradation. These results demonstrate the feasibility of the novel PBCFM as a robust and efficient catalyst for direct CO2 electrolysis.