Coordination Funds

基于无机纳米颗粒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，高效光吸收剂或医疗诊断材料。然而，事实上，除了合成过程中形成的初级颗粒的化学组成外，建立在它们之上的二级和三级结构的形态决定了它们的实际适用性。为了能够影响和利用这些基于结构的性质，需要高度特异性的合成，通过这种合成，可以以有针对性和可重复的方式设置组成、结构尺寸、形态和结构定义的材料组合。为了转化为实际可用的材料，气相合成作为一个连续流动的过程是特别合适的，因为它具有可扩展性和生成无配体高活性材料的能力。这就是FOR2284研究单元的作用所在：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，开发设计规则，以便在气相中定制纳米颗粒的合成，修饰和结构。这些规则涉及反应物的选择和适当的停留时间-浓度-温度分布，以及前体-粒子相互作用的可转移验证模型的发展。将一系列独特的实验（激波管中的零维实验到湍流中的三维实验）与建模相结合，可以得出稳健的规则。第二阶段的两个里程碑式的结果为粒子合成开辟了意想不到的可能性，这将在第三阶段被集中利用，并使用现有的非凡多样的跨学科工具包来实施。结果表明：(1)中间部分氧化颗粒相的存在：在火焰合成的氧化铁中检测到金属铁，在合成的SiO2中检测到中间SiO2颗粒。这一意想不到的结果为研究（强）亚化学计量氧化物提供了一个非常有趣的方法。通过快速反应中断和涂层来稳定这些，从而使一类新的材料可作为产品使用，是第三个阶段的中心目标。(2)由于施密特数效应及其对颗粒生长、包覆和聚集的影响而产生的小尺度陡峭浓度梯度的存在：通过有针对性地改变反应流中的湍流程度来控制这些影响，为干预初级颗粒和包覆材料的形态提供了可能。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。整合这些方面将使在连续流过程中生产以前不可预见的材料类别成为可能。

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.