The flame spray pyrolysis of iron oxide nanoparticles using the new reference nozzle SpraySyn is a key step towards the understanding of the coupling of physicochemical steps such as precursor atomization, spray evaporation, combustion, particle formation and growth. Owing to the countless available solvents and precursors, systematic investigations are necessary to fully understand the impact of precursor formulation on the reaction route and, hence, the particle properties. In this work, the recently developed phase-selective laser-induced breakdown spectroscopy (PS-LIBS) technique is applied to an external mixing spray flame reactor in order to study iron oxide particle formation along the axial centerline of the spray under varying precursor solutions. The addition of 2-ethylhexanoic acid (EHA) to precursors is investigated and significant differences in the evolution of the atomic emission spectra are observed, enabling the differentiation between droplet-to-particle and gas-to-particle routes in situ. The observations from PS-LIBS are in good agreement with TEM images and XRD, where haematite (α-Fe₂O₃), maghemite (γ-Fe₂O₃), and magnetite (Fe₃O₄) were observed. Raman spectroscopy (RS) in particle-free spray-flames revealed a significant gas-phase temperature difference of about ΔT∼500 K under addition of EHA to the spray and demonstrated accurate temperature measurements up to droplet rates of 10³ Hz. The experimental results allow deep insights into the spray flame combustion and particle nucleation kinetics. Moreover, they can be coupled with population balance models and be used for the validation of numerical simulations.

使用新的参考喷嘴SpraySyn对氧化铁纳米颗粒进行火焰喷雾热解是理解物理化学步骤（例如前体雾化，喷雾蒸发，燃烧，颗粒形成和生长）耦合的关键步骤。由于有无数种可用的溶剂和前体，必须进行系统研究才能充分了解前体配方对反应路线的影响，并因此全面了解颗粒的性质。在这项工作中，最近开发的相选择激光诱导击穿光谱技术（PS-LIBS）技术应用于外部混合喷雾火焰反应器，以便研究在各种前体溶液下沿喷雾轴向中心线形成的氧化铁颗粒。原地。从PS-LIBS的观察结果与TEM图像和X射线衍射，其中赤铁矿（α-铁吻合₂ ö ₃），磁赤铁矿（γ-的Fe ₂ ö ₃）和磁铁矿（铁₃ ö ₄）中观察到。在无粒子喷雾火焰中的拉曼光谱（RS）显示，在向喷雾中添加EHA时，气相温度差约为ΔT〜500 K，并显示了高达10 ³  Hz的液滴速率的精确温度测量值。实验结果可以深入了解喷雾火焰燃烧和颗粒成核动力学。此外，它们可以与人口平衡模型耦合，并用于验证数值模拟。