Unveiling the Key Magnetic Factors Governing Efficient Ortho-Para Hydrogen Conversion on Superparamagnetic Iron Oxide

作者：Jiuyi Wang, Zheng Shen, El Mehdi Chatir, Yusen Chen, Weijue Wang, Hongying Zhuo, Xiaofeng Yang, Guodong Liu, Xuning Li, Yanqiang Huang, Tao Zhang · 发表于：Energy & Fuels · 年份：2025 · DOI：10.1021/acs.energyfuels.5c03658 · 被引用次数：4 · 研究领域：Chemical Looping and Thermochemical Processes、Hydrogen Storage and Materials、Catalysts for Methane Reforming

High Resolution Image Download MS PowerPoint Slide Ortho-para hydrogen ( o-p H 2 ) conversion is a key step in enabling efficient liquid hydrogen storage and transportation. Nevertheless, the development of highly efficient o-p H 2 conversion catalysts is still limited by an incomplete understanding of how structural and magnetic properties control the catalytic performance. Herein, this work reports the controlled synthesis of superparamagnetic iron oxides (FeO x ) via a modified thermal decomposition method and elucidates the influence of their magnetic properties on the o-p H 2 conversion efficiency. Notably, FeO x -2 (pyrolyzed at 473 K) exhibits a rate constant 1.6 times higher than that of the commercial catalyst. Results from structural characterization and vibrating sample magnetometry measurements reveal that the specific surface area and magnetization significantly influence the o-p H 2 conversion efficiency. Furthermore, low-temperature (2.6−298 K) 57 Fe Mössbauer spectroscopy reveals that superparamagnetic FeO x exhibiting a lower blocking temperature and shorter relaxation time promotes rapid magnetic moment reversal, thereby enhancing the o-p H 2 conversion. Additionally, low-temperature H-D exchange experiments suggest the nondissociative magnetic reaction mechanism over superparamagnetic FeO x . This study clarifies the critical role of intrinsic magnetic properties in superparamagnetic iron oxides for efficient o-p H 2 conversion, providing fundamental princi...