Journal of Nanoparticle Research

, Volume 12, Issue 5, pp 1765–1775

The effects of vacuum annealing on the structure and surface chemistry of iron nanoparticles

  • Thomas B. Scott
  • Michelle Dickinson
  • Richard A. Crane
  • Olga Riba
  • Gareth M. Hughes
  • Geoffrey C. Allen
Research Paper

DOI: 10.1007/s11051-009-9732-9

Cite this article as:
Scott, T.B., Dickinson, M., Crane, R.A. et al. J Nanopart Res (2010) 12: 1765. doi:10.1007/s11051-009-9732-9

Abstract

In order to increase the longevity of contaminant retention, a method is sought to improve the corrosion resistance of iron nanoparticles (INP) used for remediation of contaminated water and thereby extend their industrial lifetime. A multi-disciplinary approach was used to investigate changes induced by vacuum annealing (<5 × 10−8 mbar) at 500 °C on the bulk and surface chemistry of INP. The particle size did not change significantly as a result of annealing but the surface oxide thickness decreased from an average of 3–4 nm to 2 nm. BET analysis recorded a decrease in INP surface area from 19.0 to 4.8 m2 g−1, consistent with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations which indicated the diffusion bonding of previously discrete particles at points of contact. X-ray diffraction (XRD) confirmed that recrystallisation of the metallic cores had occurred, converting a significant fraction of poorly crystalline iron to bcc α-Fe and Fe2B phases. X-ray photoelectron spectroscopy (XPS) indicated a change in the surface oxide stoichiometry from magnetite (Fe3O4) towards wüstite (FeO) and the migration of boron and carbon to the particle surfaces. The improved core crystallinity and the presence of passivating impurity phases at the INP surfaces may act to improve the corrosion resistance and reactive lifespan of the vacuum annealed INP for environmental applications.

Keywords

IronNanoparticlesVacuum annealXPSEnvironmental remediation

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Thomas B. Scott
    • 1
  • Michelle Dickinson
    • 1
  • Richard A. Crane
    • 1
  • Olga Riba
    • 1
  • Gareth M. Hughes
    • 2
  • Geoffrey C. Allen
    • 1
  1. 1.Interface Analysis CentreUniversity of BristolBristolUK
  2. 2.Department of MaterialsOxford UniversityOxfordUK