Coordination Funds

基于无机纳米粒子的功能材料具有巨大的应用潜力，例如，作为高效的能量存储装置、无贵金属催化剂、高效的光吸收剂或用于医疗诊断的材料。然而，事实上，除了在合成过程中形成的初级颗粒的化学组成之外，基于它们构建的二级和三级结构的形态决定了它们的实用性。为了能够影响和利用这些基于结构的特性，需要高度特异性的合成，通过该合成，可以以目标和可再现的方式设定组成、结构尺寸、形态和结构限定的材料组合。为了转化成实际可用的材料，作为连续流动方法的气相合成由于其可扩展性和其产生无配体的高活性材料的能力而特别适合。这就是研究单元FOR 2284的用武之地：通过了解前体化学、颗粒形成、颗粒-颗粒相互作用和原位功能化的基本步骤，开发了设计规则，使纳米颗粒在气相中的定制合成、改性和结构化成为可能。这些规则涉及反应物和适当的停留时间-浓度-温度曲线的选择，以及可转移的验证模型的开发，用于粒子-粒子相互作用。将一系列独特的实验（激波管中的零维到湍流中的三维）与建模相结合，导致了鲁棒规则的发展。第二阶段的两个具有里程碑意义的结果开辟了粒子合成的意想不到的可能性，这将在第三阶段得到深入的利用，并使用现有的非常多样化的跨学科工具包实施。这些结果是：（1）中间部分氧化颗粒相的出现：在氧化铁的火焰合成中检测到金属铁，在SiO2的合成中检测到中间SiO颗粒。这个意想不到的结果提供了一个非常有趣的方法（强）亚化学计量的氧化物。通过快速反应中断和涂层来稳定这些材料，从而使一类新材料作为产品可获得，是第三阶段的中心目标。(2)由于施密特数效应及其对颗粒生长、涂层和聚集的影响，存在小规模的陡峭浓度梯度：通过有针对性地改变反应流中的湍流程度来控制这些效应，开辟了干预初级颗粒和涂层材料形态的可能性。研究小组的中心任务之一是更详细地调查和利用这一点，特别是在中试工厂规模上。整合这些方面将使人们有可能在连续流动过程中生产以前不可预见的材料类别。

Functional materials based on inorganic nanoparticles have great application potential, e.g., as highly potent energy storage devices, noble metal-free catalysts, efficient light absorbers or materials for medical diagnostics. In fact, however, in addition to the chemical composition of the primary particles formed in the synthesis process, the morphology of the secondary and tertiary structures built upon them determines their practical applicability. In order to be able to influence and utilize these structure-based properties, highly specific synthesis is required, with which composition, structure size, morphology and structurally defined material combinations can be set in a targeted and reproducible manner. For transfer into practically usable materials, gas-phase synthesis as a continuous flow process is particularly suitable due to its scalability and its ability to generate ligand-free highly active materials. This is where the research unit FOR2284 comes in: By understanding the elementary steps of precursor chemistry, particle formation, particle-particle interaction, and in situ functionalization, design rules are developed that enable tailored synthesis, modification, and structuring of nanoparticles in the gas phase. These rules involve the selection of reactants and appropriate residence time-concentration-temperature profiles, as well as the development of transferable validated models for precursor-particle interaction. Coupling a unique range of experiments (zero-dimensional in shock tubes to three-dimensional in turbulent flows) with modeling leads to the development of robust rules. Two landmark results of the second period open up unexpected possibilities in particle synthesis, which will be intensively exploited in the third period and implemented using the available extraordinary diverse interdisciplinary toolkit. These results are: (1) Occurrence of intermediate partially oxidized particle phases: Metallic iron was detected in the flame synthesis of iron oxide, and intermediate SiO particles in the synthesis of SiO2. This unexpected result provides a highly interesting approach to (strongly) sub-stoichiometric oxides. Stabilizing these by rapid reaction interruption and coating, thus making a new class of materials accessible as a product, is a central goal of the third period. (2) Existence of small-scale steep concentration gradients due to Schmidt number effects and their impact on particle growth, coating, and aggregation: Controlling these effects by a targeted variation of the degree of turbulence in the reacting flow opens up the possibility to intervene in the morphology of both the primary particles and the coated materials. One of the central tasks of the research group is to investigate and exploit this in more detail, especially on a pilot plant scale. Integrating these aspects will make it possible to produce previously unforeseeable classes of materials in continuous flow processes.