Photocatalytic activity of non-stoichiometric ZnFe2O4 under visible light irradiation

A. Šutka, R. Pärna, J. Kleperis, T. Käämbre, I. Pavlovska, V. Korsaks, K. Malnieks, L. Grinberga, V. Kisand

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

Nanostructured zinc ferrites with different excess iron contents (ZnFe 2+zO4, where z = 0.00, 0.05, 0.10 and 0.15) have been synthesized using the sol-gel auto-combustion method. The effect of excess iron on the structural, optical and visible light photocatalytic activity of zinc ferrite samples has been investigated. X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), x-ray magnetic circular dichroism (XMCD), Brunauer-Emmett-Teller theory, scanning electron microscopy (SEM), diffuse reflectance spectroscopy (UV-Vis) and photoluminescence spectroscopy were used to characterize the synthesized non-stoichiometric ZnFe2O4 powders. The XRD patterns demonstrated that the samples consist of single phase spinel structure with crystallite sizes of ∼25 nm. SEM analysis indicated that the nanosized particles grow together in porous clusters with a size of several microns. The XPS and XMCD analyses revealed that the excess iron ion substitutes Zn2+ in tetrahedral sites and in octahedral sites Fe 2+ can be found in addition to Fe3+, which could be created to restore the overall charge balance in the crystal lattice. Stoichiometric zinc ferrite (ZnFe2+zO4, z = 0.00) exhibited higher photocatalytic activity (40%) than the excess iron sample (ZnFe2+zO4, z = 0.15, i.e. 4%) under visible light irradiation for 3 h. This was explained by the formation of Fe2+ in the octahedral sites of excess iron ZnFe2O4; these species act as recombination centres.

Original languageEnglish
Article number044011
JournalPhysica Scripta
Volume89
Issue number4
DOIs
Publication statusPublished - Apr 2014
Externally publishedYes

Keywords*

  • photocatalyst
  • photoluminescence
  • sol-gel combustion
  • visible light
  • x-ray magnetic circular dichroism
  • XPS
  • zinc ferrite

Field of Science*

  • 1.3 Physical sciences

Publication Type*

  • 1.1. Scientific article indexed in Web of Science and/or Scopus database

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