Development of New Precursors and Processes for the Controlled Deposition of Platinum Groups Metals

铂族金属（PGM: Ru, Rh, Pd, Os， Ir和Pt）可以以分子形式（均相催化）或作为纳米结构材料（非均相催化）应用，作为高效催化剂广泛应用于有机化合物的化学合成或燃料电池应用。由于其丰度低且具有挑战性，最近的研究往往集中在具有类似催化活性、更有效利用或环境友好回收策略的无pgm替代品上。本研究将有助于通过化学气相沉积（CVD）技术更有效地制备纳米结构的非均相PGM催化剂，了解其潜在的化学和物理机制。CVD方法允许实现无溶剂，稳定和均匀的材料沉积，甚至在开放多孔衬底内，这对于高效催化剂材料至关重要。因此，对具有高挥发性和匹配反应性的特定分子前体的可用性、理解和控制对于通过气相进行靶向沉积至关重要。将新制备的PGM前体文库与现有前体的化学性质和物理性质进行比较，分别建立反应性和挥发性的分子结构-性质关系。除了前驱体化学外，使用匹配沉积策略对每个前驱体进行靶向材料合成对于深入分析潜在的反应途径至关重要。只有对材料加工的全面理解和控制，才能产生明确的催化活性表面，这本身就构成了燃料电池应用中催化活性的材料导向结构-性质关系的基础。特别是，原位和操作中的表征方法（即气态PGM前体的红外光谱分析或CVD系统中空气分解产物的质谱表征）在实际反应条件下提供了进一步的见解。该项目遵循“从分子到材料”的整体方法，强调在两个相互交织的研究重点上构建研究工作-一个前体化学和另一个以材料科学为中心。这种综合方法被认为是必要的，以评估前体对作为多相催化剂的所得材料的技术应用的影响，并将技术相关性作为一项长期目标加以解决。在PGM前体和催化剂材料的分子和材料化学方面的发现将通过与外部研究小组的合作进一步得到证实，这些研究小组将以燃料电池的理论分子和材料建模和应用为中心进行研究。

The platinum group metals (PGM: Ru, Rh, Pd, Os, Ir and Pt), which can be applied in molecular form (homogeneous catalysis) or as nanostructured materials (heterogeneous catalysis), find widespread application as highly efficient and effective catalysts in chemical synthesis of organic compounds or in fuel cell applications. Due to their low abundance and challenging mining, recent research often focusses on PGM-free alternatives with comparable catalytic activity, more efficient utilization or environmentally friendly recycling strategies. The current proposal shall contribute to a more efficient preparation of nanostructured heterogeneous PGM catalysts via chemical vapor deposition (CVD), by understanding the underlying chemical and physical mechanisms. The CVD method allows to achieve solvent-free, stable and homogeneous deposition of materials even inside of open-porous substrates, which is essential for efficient catalyst materials. Therefore, the availability, understanding and control over defined molecular precursors with high volatility and matching reactivity profile is essential for a targeted deposition via the gas phase. The chemical and physical properties of new PGM precursor libraries will be compared with existing precursors, to establish molecular structure-property relations of reactivity and volatility, respectively. Besides precursor chemistry, a target-oriented materials synthesis using a matching deposition strategy for each precursor is crucial for in-depth analysis of underlying reaction pathways. Only a comprehensive understanding and control of material processing, yields defined catalytically active surfaces, which in itself forms the foundation of materials-oriented structure-property relations for the catalytic activity in fuel cell applications, for example. In particular, in-situ and in-operando characterization methods (i.e. IR spectroscopic analysis of gaseous PGM precursors or mass spectrometric characterization of air-borne decomposition products in CVD systems) unlock further insights under realistic reaction conditions. This project follows the holistic approach "from molecules to materials", which is underlined by structuring the research efforts in two intertwined research foci - one precursor chemistry and the other materials science centered. This integrated approach is considered necessary to assess the precursor influence on the technological application of the resulting materials as heterogeneous catalysts and addressing the technological relevance as a long-term objective. The findings on the molecular and materials chemistry of PGM precursors and catalyst materials will be further corroborated by collaborations with external research groups contributing with theoretical molecular and materials modelling and application centered fuel cell research.