Interface pH regulation to improve ORR performance of FePc catalyst in acid electrolyte

• Published in: Electrochemistry communications Vol. 141; p. 107357
• Main Authors: Li, Yu-Yang, Wang, Yu-Cheng, Zhou, Zhi-You, Sun, Shi-Gang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2022; Elsevier
• Subjects: In situ Raman spectroscopy; Interface environment; Macrocyclic compound; Non-precious metal catalysts; Oxygen reduction reaction; Non-precious metal catalysts; Interface environment; Macrocyclic compound; Oxygen reduction reaction; In situ Raman spectroscopy
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2022.107357

[Display omitted] •ORR performance of FePc is greatly improved by anion-exchange ionomer in acidic medium.•Anion-exchange ionomer can increase local pH of electrode/electrolyte interface.•The increase in interface pH was verified by in situ Raman technology. Iron–nitrogen doped carbon (Fe/N/C) electrocatalysts are among the most promising materials to replace Pt for the oxygen reduction reaction (ORR). Up to now, most work has been devoted to improving the performance of Fe/N/C catalysts by material design, while ignoring the design of the electrode/electrolyte interface environment. Considering the superior ORR performance of Fe/N/C catalysts in alkaline electrolyte, we attempt to construct a proton-deficient environment at the electrode surface to raise the local pH value. An anion-exchange ionomer with H+ blocking ability was chosen as the binder of the iron phthalocyanine (FePc) catalyst, a model molecule for Fe/N/C. The anion-exchange ionomer can increase the interface pH value as compared with commonly used Nafion binder, which was verified by the electrochemical shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) technique with CO32–/HCO3– as a probe. This strategy significantly improves the ORR activity and stability of the FePc catalyst in acidic medium.