Fe-doped nanostructured titanates synthesized in a single step route

A. M L M Costa, B. A. Marinkovic, N. M. Suguihiro, David Smith, M. E H M Da Costa, S. Paciornik

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

In this research nanostructured titanates, containing iron in the structure, were obtained through a single-step alkaline hydrothermal route aiming at reduction of band-gap energy. In the process, a Fe-Ti rich Brazilian mineral sand was mixed with 10 M of NaOH and then submitted to isothermal treatments at temperatures ranging from 110 to 190 °C in an autoclave. The as-obtained products were water-washed and then characterized by transmission electron and scanning transmission electron microscopies, X-ray photoelectron, Mössbauer and diffuse reflectance spectroscopies. Transmission electron microscopy analyses showed a morphological dependence of the product as a function of the temperature, i.e., titanate nanosheets were predominantly formed at lower temperatures (110°C-150°C), while nanoribbons, with some nanosheets and nanoparticles, were the main products at higher temperatures (> 150°C). Using energy dispersive X-ray it was determined that iron was incorporated into nanosheets. On the other hand, the as-obtained nanoribbons were Fe-free, while iron was principally associated with nanoparticles attached to the nanoribbons. By means of X-ray photoelectron and Mössbauer spectroscopies, it was elucidated that iron adopted Fe3 + form in the as-prepared nanosheets, occupying octahedral sites inside the titanate lepidocrocite-like structure. Diffuse reflectance spectroscopy showed a change of absorption pattern from nanosheets to nanoribbon/nanoparticle assembly: nanosheets exhibited high absorption from ultraviolet up to the visible light range, while the nanoribbon/nanoparticle assembly demonstrated a drop in absorption in the visible light range. These results suggest that Fe3 + incorporation inside the titanate structure is responsible for enhancing the visible light absorption, making these nanosheets potentially suitable for applications in photoinduced processes.

Original languageEnglish (US)
Pages (from-to)150-159
Number of pages10
JournalMaterials Characterization
Volume99
DOIs
StatePublished - Jan 2015

Keywords

  • Alkaline hydrothermal synthesis
  • Fe-doped titanate
  • Mineral sand
  • Nanomaterials

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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  • Cite this

    Costa, A. M. L. M., Marinkovic, B. A., Suguihiro, N. M., Smith, D., Da Costa, M. E. H. M., & Paciornik, S. (2015). Fe-doped nanostructured titanates synthesized in a single step route. Materials Characterization, 99, 150-159. https://doi.org/10.1016/j.matchar.2014.11.029