In situ reduction of as-prepared γ-Iron Oxide Nanoparticles

Pelle Gorm Garbus, Jakob Ahlburg, Mogens Christensen, Henrik Lyder Andersen, Lukas Keller

Research output: Contribution to conferencePosterCommunication


Magnetic materials are a hot topic among energy-materials and they find applications in nearly all everyday consumer electronics. Advances in magnetic performance have in particular been made for thin film and nanosized particles because the magnetic properties are strongly related to the size. Bulk iron is relatively unreactive, however nanosized iron particles are highly reactive as a result of their enlarged high surface area and the oxidation potential of iron.Iron oxides are cheap and unreactive precursors for the production of nanosized iron particles. Understanding the mechanisms behind the structural development [1, 2] adds to the fundamental understanding of materials’ formation and can lead to new synthesis pathways. In this study, iron oxide (γ-Fe2O3) particles were heated to 400°C under a flow of H2/Ar mixture, while the process was followed by in situ synchrotron powder X-ray diffraction measurement. The as-prepared maghemite nanoparticles were synthesized by the continuous decomposition of solutes in supercritical hydrothermal flow synthesis [3, 4]. The reagent used was ferric ammonium citrate (C6H8O7•xFe(III)•yNH3) that under hydrothermal flow synthesis decomposes into the γ-iron oxide Fe2O3. The reduction of maghemite to body centered cubic (BCC) iron does not go through a detectable intermediate state.1.Jensen, K.M., et al., Mechanisms for iron oxide formation under hydrothermal conditions: an in situ total scattering study. ACS nano, 2014. 8(10): p. 10704-10714.2.Andersen, H.L., et al., Size and Size Distribution Control of γ-Fe2O3 Nanocrystallites: An in Situ Study. Crystal Growth & Design, 2014. 14(3): p. 1307-1313.3.Bondesgaard, M., et al., Guide to by-products formed in organic solvents under solvothermal conditions. The Journal of Supercritical Fluids, 2016. 113: p. 166-197.4.Bremholm, M., M. Felicissimo, and B.B. Iversen, Time‐Resolved In Situ Synchrotron X‐ray Study and Large‐Scale Production of Magnetite Nanoparticles in Supercritical Water. Angewandte Chemie, 2009. 121(26): p. 4882-4885.
Translated title of the contributionIn situ reduktion af tidligere beskrevet syntetiseret γ-jern oxid nanopartikler
Original languageEnglish
Publication date28 Aug 2016
Number of pages1
Publication statusPublished - 28 Aug 2016
Event30th European Crystallographic Meeting - Congress Center Basel, Basel, Switzerland
Duration: 28 Aug 20161 Sept 2016


Conference30th European Crystallographic Meeting
LocationCongress Center Basel
Internet address

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