Time-resolved <i>in situ</i> studies on the formation mechanism of iron oxide nanoparticles using combined fast-XANES and SAXS

Kabelitz, Anke; Guilherme, A.; Joester, Maike; Reinholz, Uwe; Radtke, Martin; Bienert, Ralf; Schulz, Kirk H.; Schmack, Roman; Kraehnert, Ralph; Emmerling, Franziska

doi:10.1039/c5ce01585e

Cited by 20 publications

(12 citation statements)

References 56 publications

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“…The acquired knowledge would facilitate the control of the formation of NPs in solution and tailor the properties of the final product. 41 In another publication, Leveneur et al investigated the nucleation and growth of Fe NPs in SiO 2 by TEM, XPS and XANES. It was demonstrated that ion implantation initially resulted in the formation of dilute cationic Fe 2+ species, while at higher dissolved iron concentrations, the formation of small metallic nuclei was noticed, which seed the nanocluster growth during prolonged implantation or annealing.…”

Section: X-ray-based Techniquesmentioning

confidence: 99%

Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

2018

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Nanostructures have attracted huge interest as a rapidly growing class of materials for many applications. Several techniques have been used to characterize the size, crystal structure, elemental composition and a variety of other physical properties of nanoparticles. In several cases, there are physical properties that can be evaluated by more than one technique. Different strengths and limitations of each technique complicate the choice of the most suitable method, while often a combinatorial characterization approach is needed. In addition, given that the significance of nanoparticles in basic research and applications is constantly increasing, it is necessary that researchers from separate fields overcome the challenges in the reproducible and reliable characterization of nanomaterials, after their synthesis and further process (e.g. annealing) stages. The principal objective of this review is to summarize the present knowledge on the use, advances, advantages and weaknesses of a large number of experimental techniques that are available for the characterization of nanoparticles. Different characterization techniques are classified according to the concept/group of the technique used, the information they can provide, or the materials that they are destined for. We describe the main characteristics of the techniques and their operation principles and we give various examples of their use, presenting them in a comparative mode, when possible, in relation to the property studied in each case.

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Section: X-ray-based Techniquesmentioning

confidence: 99%

Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

2018

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“…Recent examples utilised flow cells for small angle X-ray scattering (SAXS) and X-ray diffraction (XRD), mostly using synchrotron set-ups. [23][24][25][26][27] The in-line monitoring of the MNPs' magnetic properties during synthesis, however, has been reported with techniques not requiring special facilities. [28][29][30][31] Milosevic et al monitored the evolution of magnetic properties during a co-precipitation synthesis of iron oxide nano particles (IONPs) via the MIAtek® technology.…”

Section: Introductionmentioning

confidence: 99%

Development of an in-line magnetometer for flow chemistry and its demonstration for magnetic nanoparticle synthesis

et al. 2021

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“…The solid-phase products, forming for h 4 0.5 in iron aqueous solutions, have been exhaustively studied to explore structure, size, and morphology. 15,16,[18][19][20][21][22][23][24][25] Experimental methods applied include titration, UV-vis spectroscopy, 26,27 wide-and small-angle X-ray scattering (WAXS and SAXS), 19,28,29 X-ray absorption (XA) spectroscopy, 19,20,23,24,26,[29][30][31][32] and electron microscopy. 33 In the case of FeCl 3 aqueous solutions, the different experiments find that akaganeite (b-FeOOH) forms, for h 4 0.5.…”

Section: Introductionmentioning

confidence: 99%

Detection of the electronic structure of iron-(iii)-oxo oligomers forming in aqueous solutions

Seidel

Kraffert

Kabelitz

et al. 2017

Phys. Chem. Chem. Phys.

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The nature of the small iron-oxo oligomers in iron-(iii) aqueous solutions has a determining effect on the chemical processes that govern the formation of nanoparticles in aqueous phase. Here we report on a liquid-jet photoelectron-spectroscopy experiment for the investigation of the electronic structure of the occurring iron-oxo oligomers in FeCl aqueous solutions. The only iron species in the as-prepared 0.75 M solution are Fe monomers. Addition of NaOH initiates Fe hydrolysis which is followed by the formation of iron-oxo oligomers. At small enough NaOH concentrations, corresponding to approximately [OH]/[Fe] = 0.2-0.25 ratio, the iron oligomers can be stabilized for several hours without engaging in further aggregation. Here, we apply a combination of non-resonant as well as iron 2p and oxygen 1s resonant photoelectron spectroscopy from a liquid microjet to detect the electronic structure of the occurring species. Specifically, the oxygen 1s partial electron yield X-ray absorption (PEY-XA) spectra are found to exhibit a peak well below the onset of liquid water and OH (aq) absorption. The iron 2p absorption gives rise to signal centered between the main absorption bands typical for aqueous Fe. Absorption bands in both PEY-XA spectra are found to correlate with an enhanced photoelectron peak near 20 eV binding energy, which demonstrates the sensitivity of resonant photoelectron (RPE) spectroscopy to mixing between iron and ligand orbitals. These various signals from the iron-oxo oligomers exhibit maximum intensity at [OH]/[Fe] = 0.25 ratio. For the same ratio, we observe changes in the pH as well as in complementary Raman spectra, which can be assigned to the transition from monomeric to oligomeric species. At approximately [OH]/[Fe] = 0.3 we begin to observe particles larger than 1 nm in radius, detected by small-angle X-ray scattering.

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Time-resolved in situ studies on the formation mechanism of iron oxide nanoparticles using combined fast-XANES and SAXS

Cited by 20 publications

References 56 publications

Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

Development of an in-line magnetometer for flow chemistry and its demonstration for magnetic nanoparticle synthesis

Detection of the electronic structure of iron-(iii)-oxo oligomers forming in aqueous solutions

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