Structural transformations of heat-treated bacterial iron oxide

Author(s)

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

Abstract

A bacterial siliceous iron oxide microtubule (diameter: ca. 1 μm, 15Fe

₂O

₃·8SiO

₂·P

₂O

₅·30H

₂O) 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 FeO

₆ 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.

Organisation(s)

Dynamics of Condensed Systems

External organisation(s)

Japan Synchrotron Radiation Research Institute, Okayama University, Japan Science and Technology Agency , Kyoto University, Ritsumeikan University

Journal

Materials Chemistry and Physics

Volume

155

Pages

67-75

No. of pages

9

ISSN

0254-0584

DOI

https://doi.org/10.1016/j.matchemphys.2015.01.067

Publication date

04-2015

Peer reviewed

Yes

Austrian Fields of Science 2012

103018 Materials physics

Keywords

ASJC Scopus subject areas

Condensed Matter Physics, Materials Science(all)

Portal url

https://ucrisportal.univie.ac.at/en/publications/structural-transformations-of-heattreated-bacterial-iron-oxide(63081ad9-209d-4099-a968-60e6341077ff).html