Earth abundant metal catalysts stabilized by porous N-doped carbon

多孔氮掺杂碳稳定地球上丰富的金属催化剂

• 批准号: 461481491
• 负责人: Professor Dr. Rhett Kempe
• 金额: --
• 依托单位: Arbeitsgruppe Anorganische Chemie II
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/461481491?language=en
• 关键词: Earth; abundant; metal; catalysts; stabilized

The replacement of rare noble metals by earth abundant metals has been demonstrated successfully for homogenous catalysts in recent years. Reusable and nano-structured hydrogenation and dehydrogenation catalysts, based on abundantly available metals, with a broad scope in organic synthesis have been developed to a much lesser extent. The main criticism arose from the observation that earth abundant metal are much less active in nanostructured catalyst in comparison to noble metals. Polymer based SiCN and SiC materials combine material specific characteristics such as thermal robustness and corrosion resistance with easy processing and possible shaping or structuring at low temperatures in diverse organic solvents. This easy processing also permits the synthesis of highly active catalysts.In four published manuscripts, in “Angewandte Chemie”, in “Nature Communication” (2x), and in “Nature Catalysis”, the potential of metal-SiCN nanocomposites as reusable catalysts and our expertise in 3d-metal catalysis (heterogeneous) have been demonstrated. In this project, we plan to show that nanostructured 3d-metal catalysts could be superior in activity and selectivity compared to noble metal catalysts and propose 1. the development of novel porous N-doped SiC supports and 2. the design of active and selective 3d-metal catalysts for hydrogenation and dehydrogenation reactions. Both aims are strongly linked since the support synthesis is the basis for developing novel highly active catalysts.Regarding 1.: SiCN and SiC have material specific advantages and disadvantages as porous supports for metal catalysts. SiCN gave significantly smaller and more reactive metal nanoparticles while the generation of high specific surfaces is a problem. The stabilization of especially small and reactive metal nanoparticles can be explained by the presence of N-atoms in the supports. They stabilize metal ions and clusters or particles via coordination during synthesis and catalysis to suppress growth of larger aggregates. SiC is easier to synthesize since the precursor polymers are not hydrolysis sensitive and higher specific surfaces can be generated. Unfortunately, the N-atoms which stabilize very small and highly reactive metal nanoclusters or particles are not present. A combination of the advantages would be porous N-doped SiC. Preliminary works support this hypothesis. Regarding 2.: In this subproject, we are interested in: a) the cobalt catalyzed reductive amination for the synthesis of primary amines under mild conditions, b) the hydrogenation of nitriles in the presence of functional groups easily to hydrogenate, and c) the design of selective (de)hydrogenation catalysts of so far rarely or never used 3d metals.

近年来在均相催化剂上成功地证明了富土金属替代稀有贵金属的作用。可重复使用和纳米结构的加氢和脱氢催化剂，以丰富的金属为基础，在有机合成中具有广泛的应用范围，但在较小程度上得到了发展。主要的批评来自于观察到，与贵金属相比，富含地球的金属在纳米结构催化剂中的活性要低得多。聚合物基SiCN和SiC材料结合了材料的特定特性，如热坚固性和耐腐蚀性，易于加工，并在各种有机溶剂的低温下形成或结构。这种简单的处理还允许合成高活性催化剂。在《Angewandte Chemie》、《Nature Communication》（2x）和《Nature Catalysis》上发表的四篇论文中，证明了金属- sicn纳米复合材料作为可重复使用催化剂的潜力，以及我们在3d金属催化（多相）方面的专业知识。在这个项目中，我们计划证明纳米结构的3d金属催化剂在活性和选择性上优于贵金属催化剂，并提出1。新型多孔n掺杂碳化硅支架的研制；用于加氢和脱氢反应的活性和选择性3d金属催化剂的设计。这两个目标紧密相连，因为载体合成是开发新型高活性催化剂的基础。关于1。作为金属催化剂的多孔载体，SiCN和SiC具有材料特有的优点和缺点。SiCN提供了更小和更活泼的金属纳米颗粒，而高比表面的产生是一个问题。特别是小而活泼的金属纳米颗粒的稳定性可以用n原子在载体中的存在来解释。它们在合成和催化过程中通过配位来稳定金属离子和团簇或颗粒，以抑制较大聚集体的生长。由于前驱体聚合物对水解不敏感，可以产生更高的比表面，因此碳化硅更容易合成。不幸的是，稳定非常小和高活性的金属纳米团簇或颗粒的n原子不存在。这些优点的结合将是多孔的n掺杂SiC。初步研究支持这一假设。关于2。在这个子项目中，我们感兴趣的是：a)在温和条件下钴催化还原胺化合成伯胺，b)在容易氢化的官能团存在下腈的氢化，以及c)迄今很少或从未使用过的3d金属的选择性（脱）氢化催化剂的设计。