Achieving electrocatalytic activity toward oxygen reduction reaction based on Ruddlesden-Popper type cathode catalyst for solid oxide fuel cells

Solid Oxide Fuel Cells (SOFCs) are a new type of fuel cell that directly converts chemical energy into electrical energy and have attracted widespread attention in recent years. However, the slow oxygen reduction reaction (ORR) at the cathode is one of the main factors limiting the electrochemical performance of SOFCs.

Ruddlesden-Popper (R-P) oxides have been extensively studied as cathode materials for SOFCs due to their high oxygen mobility and relatively good electrocatalytic activity. Their unique layered structure, characterized by alternating rock-salt layers and perovskite layers, allows them to maintain a large oxygen non-stoichiometry. This structural feature enables faster oxygen exchange rates and contributes to excellent structural stability. Sr₃Fe₂O₇₋_δ is composed of SrO rock-salt layers and double-layered SrFeO_3₋δ perovskite. Studies have shown that it possesses high structural stability and high oxygen ion conductivity.

Recently, a research team led by Professor Li Qiang from Heilongjiang University, China, has reported for the first time the preparation method, adsorption capacity, and electrochemical performance of a new cathode material SNFO. This study not only clarifies the mechanism of Nd doping on the oxygen reduction reaction (ORR) of SNFO but also provides a reliable option for solid oxide fuel cell (SOFC) cathode materials.

The team published their work in Journal of Advanced Ceramics on September 26, 2025.

" In this study, we synthesized a novel cathode material SNFO via the sol-gel method. Subsequently, a series of characterization and electrochemical tests were performed on this cathode material, with results indicating that the material exhibits high electrocatalytic activity and stability." stated Professor Li Qiang from the School of Chemistry and Materials Science, Heilongjiang University in Harbin, China.

Professor Li Qiang further pointed out, "DFT theoretical calculations also demonstrate that Nd doping can reduce the oxygen vacancy formation energy of the material and optimize the overall dissociation and adsorption of oxygen."

In summary, both SFO and SNFO cathode materials were successfully synthesized via the sol-gel method and systematically investigated as oxygen electrodes for SOFCs. Experimental results demonstrate that Nd doping effectively promotes oxygen vacancy formation, enhancing oxygen adsorption capacity and electrochemical performance. Notably, the SNFO cathode exhibited the Rp of 0.20 Ω cm² and PPD of 803 mW cm⁻² at 700 °C. DRT analysis combined with EIS under varying pO₂ revealed that the rate-determining step of the electrode is oxygen surface adsorption and dissociation processes. Furthermore, DFT calculations confirmed that Nd doping reduces both oxygen vacancy formation energy and adsorption energy. These findings collectively suggest that SNFO is a promising high-activity cathode catalyst for SOFCs.

However, to confirm the suitability of SNFO as a novel cathode material, more in-depth research remains necessary. Future investigations will likely focus on four core objectives: "lower operating temperature, reduced cost, extended lifespan, and broader applicability."

Other contributors include Siyue Zhang, Yingnan Dou, Tian Xia, Liping Sun, Hui Zhao from the School of Chemistry and Materials Science, Heilongjiang University in Harbin, China.

This work was supported by the National Natural Science Foundation of China (51972100) and Natural Science Foundation of Heilongjiang Province (ZD2022E007).

About Author

Li Qiang, Professor and Doctoral Supervisor at the School of Chemistry and Materials Science, Heilongjiang University, is a recipient of the "New Century Excellent Talents" support program from the Ministry of Education. He currently serves as a member of the International Society of Electrochemistry and a permanent member of the Chinese Chemical Society, Director of the Harbin International Science and Technology Cooperation Base for Solid State Ionics Materials, and Editorial Board Member of *Frontiers in Energy Research*. His research focuses on emerging areas such as novel fuel cell materials and energy storage materials, conducting internationally impactful work in these fields.

Building on his research in solid oxide fuel cells (SOFCs), he has expanded into studying the electrocatalytic performance and reduction reaction kinetics of novel oxide electrode materials. He has led over 10 national and provincial-level research projects, including those funded by the National Natural Science Foundation of China, and has received one Second-Class and two Third-Class Provincial Science and Technology Awards, along with 10 authorized invention patents. As a corresponding author, he has published more than 100 SCI-indexed papers in prestigious journals including “Advanced Energy Materials, Journal of Advanced Ceramics, Chemical Engineering Journal, Journal of Materials Science & Technology, Separation and Purification Technology, Energy, and ACS Sustainable Chemistry & Engineering. ”His publications have been cited over 4,000 times in SCI-indexed articles.

About Journal of Advanced Ceramics

Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen. JAC’s 2024 IF is 16.6, ranking in Top 1 (1/33, Q1) among all journals in “Materials Science, Ceramics” category, and its 2024 CiteScore is 25.9 (5/130) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508