Henrik Lyder Andersen is defending his Master thesis: Formation and Growth of Magnetic ?-Fe₂O₃ Nanocrystallites under Hydrothermal Conditions - An In and Ex Situ Study

Short Abstract

Magnetic iron oxide nanoparticles are of key importance in a broad range of scientific and technological applications, including permanent magnets, magnetic fluids, biomedicine, data storage and catalysis.[1-4] The properties of maghemite are highly dependent on particle size, size distribution, morphology, and particle aggregation. The formation and growth of maghemite nanocrystals during the hydrothermal synthesis from aqueous solutions of ammonium iron(III) citrate (C₆H₈O₇·xFe(III)·yNH₃) have been studied by in and ex situ powder X-ray diffraction (PXRD). Data analysis by Rietveld refinement and whole powder pattern modelling (WPPM) reveals that the crystallite size and size distributions can be precisely tuned through simple adjustments of the reaction temperature and time.[5]

[1] Lu, A. H., Salabas, E. L., Schuth, F., Angewandte Chemie, International Edition. 2007, 46, 1222-1244.

[2] Pankhurst, Q. A., Connolly, J., Jones, S. K., Dobson, J., Journal of Physics D: Applied Physics. 2003, 36, R167-R181.

[3] Vekas, L., Smart Materials & Micro/Nanosystems. 2009, 54, 127-136.

[4] Doudrick, K., Yang, T., Hristovski, K., Westerhoff, P., Applied Catalysis, B: Environmental. 2013, 136, 9-18.

[5] Andersen, H. L., Jensen, K. M. Ø., Tyrsted, C., Bøjesen, E. D., Christensen, M., Crystal Growth & Design. 2014, 14, 1307-1313.

Examiners: 

External examiner: Senior scientist Poul Norby, Department of Energy Conversion and Storage, Technical University of Denmark

Examiner / Main supervisor: Assistant Professor Mogens Christensen, iNANO and Department of Chemistry, Aarhus University