Structural transformations of heat-treated bacterial iron oxide

Hideki Hashimoto, Tatsuo Fujii, Shinji Kohara, Koji Nakanishi, Chihiro Yogi, Herwig Peterlik, Makoto Nakanishi, Jun Takada

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


A bacterial siliceous iron oxide microtubule (diameter: ca. 1 μm, 15Fe2O3·8SiO2·P2O5·30H2O) produced by Leptothrix ochracea was heat treated in air and its structural transformation was investigated in detail by microscopy, diffractometry, and spectroscopy. Although the heat-treated bacterial iron oxide retained its original microtubular structure, its nanoscopic, middle-range, and local structures changed drastically. Upon heat treatment, nanosized pores were formed and their size changed depending on temperature. The Fe-O-Si linkages were gradually cleaved with increasing temperature, causing the progressive separation of Fe and Si ions into iron oxide and amorphous silicate phases, respectively. Concomitantly, global connectivity and local structure of FeO6 octahedra in the iron oxide nanoparticles systematically changed depending on temperature. These comprehensive investigations clearly revealed various structural changes of the bacterial iron oxide which is an important guideline for the future exploration of novel bio-inspired materials.

Original languageEnglish
Pages (from-to)67-75
Number of pages9
JournalMaterials Chemistry and Physics
Publication statusPublished - Apr 1 2015


  • Amorphous materials
  • Composite materials
  • Nanostructures
  • Oxides

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics


Dive into the research topics of 'Structural transformations of heat-treated bacterial iron oxide'. Together they form a unique fingerprint.

Cite this