Enhancing catalytic activity of CO2 electrolysis via B-site cation doped perovskite cathode in solid oxide electrolysis cell

Solid oxide electrolysis cell (SOEC) is considered as a high energy-efficient CO 2 conversion method and a promising technology to achieve carbon neutralization. Thus, in this work, the reduced Co or Ni doped Pr 0.4 Sr 0.6 Fe 0.9 Mo 0.1 O 3 perovskite oxides are used as the cathode of SOEC. After reduction, Co-Fe alloy nanoparticles are in situ exsolved from Pr 0.4 Sr 0.6 Co 0.2 Fe 0.7 Mo 0.1 O 3 and Pr 0.4 Sr 0.6 Co 0.45 Fe 0.45 Mo 0.1 O 3 , and NiFe 10.8 alloy nanoparticles are attached on the Pr 0.4 Sr 0.6 Ni 0.2 Fe 0.7 Mo 0.1 O 3 matrix. The reduced Pr 0.4 Sr 0.6 Ni 0.2 Fe 0.7 Mo 0.1 O 3 exhibits the highest oxygen vacancy concentration and CO 2 adsorption ability, which further promote oxygen surface exchange and electrochemical surface exchange reaction. Besides, the reduced Pr 0.4 Sr 0.6 Ni 0.2 Fe 0.7 Mo 0.1 O 3 exhibits the highest surface reaction rate constant ( k chem ) of 3.54 × 10 -4  cm s -1 and highest oxygen chemical bulk diffusion coefficient ( D chem ) of 27.53 × 10 -5  cm 2  s -1 , suggesting that reduced Pr 0.4 Sr 0.6 Ni 0.2 Fe 0.7 Mo 0.1 O 3 shows the best catalytic activity for CO 2 reduction reaction. The symmetrical cell with reduced Pr 0.4 Sr 0.6 Ni 0.2 Fe 0.7 Mo 0.1 O 3 shows the lowest polarization resistance ( R p ) value, and at 800 °C, the electrolysis cell with reduced Pr 0.4 Sr 0.6 Ni 0.2 Fe 0.7 Mo 0.1 O 3 cathode also exhibits the best performance of 0.81 A cm -2 in 50%CO-50%CO 2 and 1.05 A cm -2 in pure CO 2 at 1.5 V, indicating that reduced Pr 0.4 Sr 0.6 Ni 0.2 Fe 0.7 Mo 0.1 O 3 is a promising cathode for CO 2 electrolysis.