Tailoring the structural stability, electrochemical performance and CO2 tolerance of aluminum doped SrFeO3

• Published in: Separation and purification technology 2022-06, Vol.290, p.120843, Article 120843
• Main Authors: Huan, Daoming, Zhang, Lu, Zhu, Kang, Li, Xinyu, Zhang, Binze, Shi, Jialin, Peng, Ranran, Xia, Changrong
• Format: Article
• Language: English
• Subjects: CO2 tolerance; DFT calculations; Oxygen reduction reaction; Solid oxide fuel cells; SrFe0.9Al0.1O3-δ
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2022.120843

Cubic SrFeO3-δ with higher oxygen vacancy concentration is stabilized via substituting Fe4+ with Al3+, showing much improved ORR electrocatalytic activity and excellent CO2 tolerance. [Display omitted] •Cubic perovskite SrFeO3-δ is stabilized with aluminum doping strategy at B-sites.•Aluminum dopant significantly improves exceeding two-fold values of Dchem and kchem.•The SFAl0.1 sample shows much improved electrocatalytic activity and CO2-tolerance.•DFT calculation results demonstrate the mechanism of enhanced electrochemical performance and CO2 tolerance. Stabilizing SrFeO3-δ in cubic structure is of great significance for its application in solid oxide fuel cells. Herein, a rational way is reported to tune the structure and performance of SrFeO3-δ perovskite as oxygen reduction electrodes by embedding aluminum cation in B-site. Compared with their parent oxide, the obtained stabilized cubic perovskites SrFe1-xAlxO3-δ (x = 0.1 and 0.2) show much improved electrocatalytic activity, achieving area specific resistance values of 0.57, 0.15 and 0.34 Ωcm2 at 700 °C in air for SrFeO3-δ, SrFe0.9Al0.1O3-δ and SrFe0.8Al0.2O3-δ, respectively. Such improved performance is a result of the exceeding 2-fold increase in oxygen chemical bulk diffusion and surface exchange kinetics due to Al3+ doping. Moreover, favorable CO2-resistance is also demonstrated. DFT calculations are carried out to reveal the accelerated oxygen reduction reaction and enhanced CO2 tolerance. This work indicates an aluminum dopant in B-site may provide a highly attractive strategy for the future development of cathode materials.