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Effect of Bi-doping on the electrocatalytic properties of LaFeO3 powders prepared by sol–gel method
- Li, Wanjun, Yang, Fujun, Xiong, Peng, Jia, Yunjie, Liu, Jiawei, Yan, Xinsui, Chen, Xiaoqin
- Journal of materials science 2019 v.54 no.10 pp. 7460-7468
- Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, catalysts, iron, oxygen, powders, sol-gel processing
- In this work, La₁₋ₓBiₓFeO₃ powders (0 ≤ x ≤ 0.2) were prepared by sol–gel route. The orthorhombic Pbnm structure of the pure LaFeO₃ powder was confirmed by X-ray diffraction. However, there was a changing tendency from the orthorhombic Pbnm structure into the rhombohedral R3c structure with the increase in Bi-doping. The structural and symmetric change of Bi-doped LaFeO₃ samples was further verified by the Raman spectra which changed from fundamental 5 modes into 7 modes. The X-ray photoelectron spectra (XPS) revealed that more oxygen vacancies, Fe³⁺ and Fe⁴⁺, existed in Bi-doped LaFeO₃ sample. Detailed CV, LSV and EIS analyses had provided conclusive evidence that the oxygen vacancy Fe³⁺ and Fe⁴⁺ played an important contribution to the electrocatalytic activity. The best ORR catalytic effect was observed in La₀.₈₅Bi₀.₁₅FeO₃ catalyst. These results suggest that the Bi-doping is a significative effort to enhance the activities of perovskite electrocatalysts.