Chemical Research in Chinese Universities ›› 2026, Vol. 42 ›› Issue (4): 1177-1192.doi: 10.1007/s40242-026-6138-5

• Review Articles • Previous Articles     Next Articles

Recent Advances in Techniques for Identifying Spin-state Species in Fe-based Metal Catalysts

GONG Tianyu2, LIU Gaoyuan1, DUAN Jiawei2, ZHANG Jia-Nan1   

  1. 1. College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China;
    2. College of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, P. R. China
  • Received:2026-06-11 Revised:2026-06-29 Online:2026-08-01 Published:2026-07-28
  • Contact: ZHANG Jia-Nan,E-mail:zjn@zzu.edu.cn E-mail:zjn@zzu.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (Nos. 22479126, U22A20107), the Key Projects of the Henan Provincial Science and Technology R&D Program Joint Fund, China (No. 222301420001), and the Project of the Distinguished Young Scholars Innovation Team of Zhengzhou University, China (No. 32320275).

Abstract: Developing high-performance non-precious metal catalysts for the oxygen reduction reaction (ORR) is crucial to advancing the commercialization of proton exchange membrane fuel cells. In recent years, the research focus has shifted from identifying geometrically active sites (e.g., Fe-N4) to elucidating a key electronic-structure descriptor: the spin state. However, the complexity and heterogeneous nature of catalyst materials pose significant challenges to the precise identification of spin species. This review systematically summarizes the latest advances in this field. Drawing on representative literature examples, it highlights how advanced spectroscopic techniques, including Mössbauer spectroscopy, X-ray absorption spectroscopy, and electron paramagnetic resonance, enable the precise characterization of Fe spin states. These methodological advances progressively uncover the fundamental structure-activity relationship between spin states and ORR activity, thereby providing crucial scientific foundations and forward-looking directions for the rational design of next-generation high-performance catalysts.

Key words: Spin, Non-precious metal catalyst, Mössbauer spectroscopy, Fe