Fe(II)-Catalyzed Transformation of Ferrihydrite with Different Degrees of Crystallinity

Yuyan Liu, Yuefei Ding, Anxu Sheng, Xiaoxu Li, Jiawei Chen, Yuji Arai, Juan Liu

Research output: Contribution to journalArticlepeer-review


Natural occurring ferrihydrite (Fh) nanoparticles have varying degrees of crystallinity, but how Fh crystallinity affects its transformation behavior remains elusive. Here, we investigated the Fe(II)-catalyzed transformation of Fh with different degrees of crystallinity (i.e., Fh-2h, Fh-12h, and Fh-85C). X-ray diffraction patterns of Fh-2h, Fh-12h, and Fh-85C exhibited two, five, and six diffraction peaks, respectively, indicating the order of crystallinity: Fh-2h < Fh-12h < Fh-85C. Fh with the lower crystallinity has a higher redox potential, corresponding to the faster Fe(II)-Fh interfacial electron transfer and Fe(III)labile production. With the increase of initial Fe(II) concentration ([Fe(II)aq]int.) from 0.2 to 5.0 mM, the transformation pathways of Fh-2h and Fh-12h change from Fh → lepidocrocite (Lp) → goethite (Gt) to Fh → Gt, but that of Fh-85C switches from Fh → Gt to Fh → magnetite (Mt). The changes are rationalized using a computational model that quantitatively describes the relationship between the free energies of formation for starting Fh and nucleation barriers of competing product phases. Gt particles from the Fh-2h transformation exhibit a broader width distribution than those from Fh-12h and Fh-85C. Uncommon hexagonal Mt nanoplates are formed from the Fh-85C transformation at [Fe(II)aq]int.= 5.0 mM. The findings are crucial to comprehensively understand the environmental behavior of Fh and other associated elements.

Original languageEnglish (US)
Pages (from-to)6934-6943
Number of pages10
JournalEnvironmental Science and Technology
Issue number17
StatePublished - May 2 2023


  • classical nucleation theory
  • crystallinity
  • dissolution-reprecipitation
  • ferrihydrite
  • interfacial electron transfer
  • labile Fe(III) production
  • redox potential
  • transformation pathways

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry


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