Enhanced oxygen reduction reaction activity of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ cathode via Pr-doping for intermediate-temperature solid oxide fuel cells

Overcoming the low activity barrier of cathode material within the intermediate-temperature range is crucial to the widespread application of solid oxide fuel cells. In this study, the perovskite La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) is modified by doping A-site cations (Pr^{3 +}) as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The characterization results indicate that La_0.6-xPr_xSr_0.4Co_0.2Fe_0.8O_3-δ (x = 0, 0.1, 0.2, 0.3) oxides are successfully synthesized using the sol-gel method, and the as-prepared samples manifest superior electrochemical performances in contrast to the parent compound (LSCF) as expected. The polarization resistance (R_P) and peak power density (PPD) of LPSCF0.3 are measured at 600 ℃, presenting the corresponding 60 % reduction in R_P and 34 % increase in PPD compare with those of undoped LPSCF0 sample. This performance improvement can be largely due to the increased oxygen vacancy concentration caused by Pr³⁺ doping, leading to the acceleration of oxygen transport rate. Meanwhile, the modified LPSCF0.3 behaves the smallest particle size, which may provide more active sites for oxygen adsorption and enhance cathode oxygen reduction reaction (ORR) activity as desired, suggesting that Pr doping can be a promising modification strategy for LSCF cathode materials in IT-SOFC.