UCL  IRIS
Institutional Research Information Service
UCL Logo
Please report any queries concerning the funding data grouped in the sections named "Externally Awarded" or "Internally Disbursed" (shown on the profile page) to your Research Finance Administrator. Your can find your Research Finance Administrator at https://www.ucl.ac.uk/finance/research/rs-contacts.php by entering your department
Please report any queries concerning the student data shown on the profile page to:

Email: portico-services@ucl.ac.uk

Help Desk: http://www.ucl.ac.uk/ras/portico/helpdesk
Publication Detail
Unravelling the growth mechanism of the co-precipitation of iron oxide nanoparticles with the aid of synchrotron X-Ray diffraction in solution.
Abstract
Co-precipitation is the most ubiquitous method for forming iron oxide nanoparticles. For a typical co-precipitation synthesis, the pH of a ferrous and/or ferric ion solution is increased via the addition of a base. The latter can be added either slowly (a steady addition over either minutes or hours) or fast (a one-time addition) resulting in an abrupt increase in the pH. However, understanding the mechanism of particle formation is still lacking, which limits the reproducibility of the co-precipitation reaction due to intermediate phases still being present in the final product. In this work, we study in detail a co-precipitation synthesis with an abrupt increase in pH via the addition of sodium carbonate. Fast and reproducible mixing at defined precursor and base solution temperatures was achieved utilising a flow reactor. Transmission electron microscopy, electron diffraction and room temperature 57Fe Mössbauer spectroscopy showed a distinct transition from an amorphous ferrihydrite phase to a mixture of magnetite-maghemite (Fe3O4/γ-Fe2O3). Synchrotron X-ray diffraction revealed the initial formation of crystalline iron hydroxide carbonate (green rust) plates occurring before the Fe3O4/γ-Fe2O3 appeared. The ferrihydrite particles increase in size over time as the proportion of iron hydroxide carbonate plates are re-dissolved into solution, until the ferrihydrite particles crystallise into Fe3O4/γ-Fe2O3.
Publication data is maintained in RPS. Visit https://rps.ucl.ac.uk
 More search options
UCL Researchers
Author
Dept of Chemical Engineering
Author
Dept of Chemical Engineering
Author
Dept of Physics & Astronomy
University College London - Gower Street - London - WC1E 6BT Tel:+44 (0)20 7679 2000

© UCL 1999–2011

Search by