Morphological and compositional changes of MFe2O4@Co3O4 (M = Ni, Zn) core-shell nanoparticles after mild reduction

A. Govender, Ezra J. Olivier, Emanuela Carleschi, Eric Prestat, Sarah J. Haigh, Hendrik van Rensburg, Bryan P. Doyle, Werner Barnard, R. P. Forbes, Johannes H. Neethling, Eric van Steen

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


NiFe2O4@Co3O4 and ZnFe2O4@Co3O4 core-shell nanoparticles were synthesized and reduced to be used as catalysts for the Fischer-Tropsch synthesis. The as-synthesized materials were determined to have an incomplete Co3O4 shell around the ferrite core with a maximum thickness of 3 nm. Using in-situ TEM, it was shown that reduction of these core-shell nanoparticles in pure hydrogen at 230 °C and 250 °C, respectively, resulted in the formation of small cobalt islands on the ferrite surface. Catalytic testing of the core-shell materials, NiFe2O4@Co3O4 and ZnFe2O4@Co3O4, after reduction showed a cobalt-time yield of 13.64 μmolCO·gCo −1·s−1 and 4.27 μmolCO·gCo −1·s−1 and a C5+ selectivity of 47 C-% and 68 C-%, respectively. The observed difference in cobalt-time yield and selectivity between NiFe2O4@Co3O4 and ZnFe2O4@Co3O4 core-shell nanoparticles was ascribed to a combination of effects that arose from the morphological and compositional changes that occurred after reduction and under Fischer-Tropsch synthesis conditions.

Original languageEnglish
Article number109806
JournalMaterials Characterization
Publication statusPublished - Sept 2019


  • Cobalt
  • Core-shell nanoparticles
  • Ferrite
  • Fischer-Tropsch synthesis
  • In-situ TEM

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


Dive into the research topics of 'Morphological and compositional changes of MFe2O4@Co3O4 (M = Ni, Zn) core-shell nanoparticles after mild reduction'. Together they form a unique fingerprint.

Cite this