Reducible oxide materials: knowledge-driven design of novel low-temperature synthesis routes

在离子液体(ILS)中低温合成可还原氧化物纳米材料具有制造具有定制结构和组成的新型材料的潜力。然而，基于知识的新合成路线的设计需要对控制粒子成核和生长的界面化学有深入的了解。该项目旨在提供这一知识，并将其应用于综合方法，结合基础界面科学、原位光谱学和真实材料的制备。我们的战略是基于Wasserscheid集团的互补专业知识，该集团拥有与IL相关材料的合成平台化学知识，利布达集团引入了其在表面科学和现场光谱分析方面的能力。此外，该项目还将受益于SPP 1708内部的密切合作。根据第一个资助期的方法发展，第二个资助期的项目特别旨在合成氧化钴纳米颗粒，这是一种在催化和能源技术中具有巨大潜力取代贵金属的材料。我们的目标是在接近室温的条件下形成具有明确组成、形状和结构的纳米材料。纳米材料将由基于咪唑和吡咯烷的ILS中的分子前体使用非传统的氧化剂如臭氧形成。我们将把IL/氧化物界面化学的基础研究与真实材料合成过程中的原位光谱相结合。因此，我们将探索ILS、分子钴前体和氧化剂臭氧之间的相互作用，确定反应机理和中间产物，使用时间分辨原位光谱提取动力学数据，并研究合成的实际方面，如优化的溶解性能。通过研究IL在氧化钴界面上的吸附、相互作用和反应的结构依赖性，我们将探索结构导向效应的起源。基于这些结果，我们的目标是利用ILS的结构多样性，例如通过改变阴离子、阳离子、取代和官能化来调节氧化物-IL的相互作用。最后，我们将把机理、光谱和动力学数据与所获得的纳米材料的性质相关联。这还将包括在合成过程中去除污染物和引入掺杂剂的策略，例如通过将ILS氧化转化为挥发性产品。遵循这一策略，我们希望对决定粒子形状、结构、大小和组成等关键性质的因素有一个基本的了解，这最终将有助于释放离子液体中低温合成氧化物纳米粒子的全部潜力。

The low-temperature synthesis of reducible oxide nanomaterials in ionic liquids (ILs) holds the potential to make novel materials with tailor-made structure and composition available. However, the knowledge-based design of new synthesis routes requires an in-depth understanding of the interfacial chemistry that controls particle nucleation and growth. The project aims at providing this knowledge and at applying it for synthesis in an integrated approach that combines fundamental interface science, in-situ spectroscopy and the preparation of real materials. Our strategy is based on the complementary expertise of the Wasserscheid Group with its know-how in synthetic bench chemistry with IL-related materials and of the Libuda Group bringing in its capabilities in surface science and in-situ spectroscopy. In addition, the project will benefit from intense cooperation within the SPP 1708. Based on the methodic developments of the first funding period, the project for the second funding period aims in particular at the synthesis of cobalt oxide nanoparticles, materials that offer great potential to replace noble metals in catalysis and energy technology. We will target the formation of nanomaterials with well-defined composition, shape and structure at near-room-temperature conditions. Nanomaterials will be formed from molecular precursors in imidazolium- and pyrrolidinium-based ILs using unconventional oxidizing agents such as ozone. We will combine fundamental studies of the IL/oxide interfacial chemistry with in-situ spectroscopy during synthesis of real materials. Thereby, we will explore the interactions between the ILs, molecular Co precursors and the oxidizing agent ozone, identify reaction mechanisms and intermediates, extract kinetic data using time-resolved in-situ spectroscopies and investigate practical aspects of synthesis such as optimized solubility properties. Investigating the structure dependence of IL adsorption, interaction and reaction at well-defined cobalt oxide interfaces, we will explore the origin of structure-directing effects. Based on these results, we aim to tune oxide-IL interactions by employing the structural diversity of ILs, e.g. by varying anions, cations, substitution and functionalization. Finally, we will correlate the mechanistic, spectroscopic and kinetic data to the properties of the nanomaterials obtained. This will also include strategies to remove contaminations and introduce dopants during synthesis, for instance by oxidative transformation of ILs into volatile products. Following this strategy, we expect to obtain fundamental insights into the factors that determine key properties such as particle shape, structure, size, and composition, which, eventually, will help to unleash the full potential of low-temperature synthesis of oxide nanoparticle in ILs.