@article{63830,
  abstract     = {{ This study investigates the effect of dispersion gas (DG) flow on the formation and properties of maghemite (γ-Fe2O3) nanoparticles using standardized SpraySyn burners (SS1 and SS2). Several diagnostics were employed to characterize the spray and nanoparticles. 
Increasing DG flow (6 - 12 slm) results in smaller droplet sizes (DS), cooler flame temperatures, shorter high-temperature droplet/particle residence times, and smaller agglomerates in the size range of 5 - 12 nm with narrower primary particle size distribution, corresponding to higher mass fractal dimensions, as supported by TEM and SMPS analysis, resulting in more compact agglomerates. BET and TEM confirmed decreasing primary particle sizes with increasing DG flow. Raman and XRD analyses predominantly identified maghemite, which shows a bimodal distribution of crystallite sizes, while SS1 samples have a greater proportion of larger crystallites.
The self-preserving size distributions of agglomerates with a geometric standard deviation of 1.5 are reached faster with increasing DG flow. The barrier effect of DG observed in SS1 leads to slower droplet combustion kinetics, higher temperatures, and delayed precursor release, which, along with downstream flow recirculation, result in significantly higher agglomeration rates outside the visible flame. SS2 demonstrates improved atomization, more stable flames, and finer, uniform nanoparticles with less carbonaceous residues (CR). Conversely, SS1 showed broader DS distributions and higher CR levels on the γ-Fe2O3 surface, especially at higher DG flow.
This work highlights the essential role of DG flow and nozzle geometry in controlling droplet evaporation, flame stability, and nanoparticle growth, offering insights for optimizing SFS and validating numerical models.
}},
  author       = {{Massopo, Orlando and Tischendorf, Ricardo and Gonchikzhapov, Munko and Kasper, Tina and Augustin, Peter and Özer, Burak and Reddemann, Manuel and Kneer, Reinhold and Sheikh, Mohammed-Ali and Mert, Aydan Akyildiz and Wiggers, Hartmut and Schmid, Hans-Joachim}},
  issn         = {{0032-5910}},
  journal      = {{Powder Technology}},
  keywords     = {{Spray flame synthesis, iron oxide nanoparticle, SpraySyn burner, Dispersion gas, Coaxial atomization, HiaT-SMPS}},
  publisher    = {{Elsevier BV}},
  title        = {{{Influence of dispersion gas flow on the spray characteristics and γ-Fe2O3 nanoparticles formation and properties in reference SpraySyn burners}}},
  doi          = {{10.1016/j.powtec.2025.121992}},
  volume       = {{470}},
  year         = {{2025}},
}

@misc{51136,
  abstract     = {{Iron oxide nanoparticles are very interesting for many applications in different industrial sectors. A promising
process to manufacture these nanoparticles is flame spray pyrolysis (FSP). A lack of understanding of the
individual sub-processes in FSP makes it challenging to tailor nanoparticle properties. This work provides
insights into the formation of iron oxide nanoparticles in a turbulent spray flame using Large Eddy Simulations
(LES), which are based on a comprehensive model, including customized submodels. Highlights are the
adaption of a turbulent combustion model and a bivariate hybrid method of moments for modeling nanoparticle
dynamics. The work focuses on the SpraySyn burner, which is a standardized laboratory burner and was
operated with a precursor-solvent mixture of ethanol and iron(III) nitrate nonahydrate. For studying the
relevance of precursor chemistry, LES using an evaporation-limited precursor chemistry model is compared
with a model that includes detailed iron chemistry. A further novelty is the inclusion of adsorption in the
simulation, which defines a third model for comparison. Sufficient validation is achieved for the undoped LES
using experimental data from the literature. A strong impact of the detailed iron chemistry and adsorption
is found on the precursor consumption and the aggregate and primary particle formation. Comparing the
particle diameters with experimental measurements from the literature and data generated for this work is
found unsuitable to asses the precursor chemistry model and revealed an urgent need for future experimental
and numerical research. This work serves as a step forward in realizing a reliable model.}},
  booktitle    = {{Applications in Energy and Combustion Science}},
  editor       = {{Fröde, Fabian  and Grenga, Temistocle  and Pitsch, Heinz  and Dupont, Sophie and Kneer, Reinhold and Tischendorf, Ricardo and Massopo, Orlando and Schmid, Hans-Joachim}},
  keywords     = {{Flame spray pyrolysis, Iron oxide formation, Large eddy simulation, Method of moments, SpraySyn}},
  publisher    = {{Elsevier}},
  title        = {{{Large eddy simulation of iron oxide formation in a laboratory spray flame}}},
  doi          = {{https://doi.org/10.1016/j.jaecs.2023.100191}},
  year         = {{2023}},
}

@article{13185,
  abstract     = {{Abstract Polylactide is a biodegradable versatile material based on annually renewable resources and thus CO2-neutral in its lifecycle. Until now, tin(II)octanoate [Sn(Oct2)] was used as catalyst for the industrial ring-opening polymerization of lactide in spite of its cytotoxicity. On the way towards a sustainable catalyst, three iron(II) hybrid guanidine complexes were investigated concerning their molecular structure and applied to the ring-opening polymerization of lactide. The complexes could polymerize unpurified technical-grade rac-lactide as well as recrystallized l-lactide to long-chain polylactide in bulk with monomer/initiator ratios of more than 5000:1 in a controlled manner following the coordination–insertion mechanism. For the first time, a biocompatible complex has surpassed Sn(Oct)2 in its polymerization activity under industrially relevant conditions.}},
  author       = {{Rittinghaus, Ruth D. and Schäfer, Pascal M. and Albrecht, Pascal and Conrads, Christian and Hoffmann, Alexander and Ksiazkiewicz, Agnieszka N. and Bienemann, Olga and Pich, Andrij and Herres-Pawlis, Sonja}},
  journal      = {{ChemSusChem}},
  keywords     = {{bioplastics, guanidines, iron, lactide, ring-opening polymerization}},
  number       = {{10}},
  pages        = {{2161--2165}},
  title        = {{{New Kids in Lactide Polymerization: Highly Active and Robust Iron Guanidine Complexes as Superior Catalysts}}},
  doi          = {{10.1002/cssc.201900481}},
  volume       = {{12}},
  year         = {{2019}},
}