Nanostructured Core-Shell-Catalysts for Fischer-Tropsch Synthesis

该项目的目标是开发一种新的方法，用于在一种催化材料中组合不同的功能。基础是纳米尺寸的核-壳材料，其目前被讨论为高温稳定的催化剂。对于在多相催化中的应用，这些材料由催化活性核和多孔壳组成。壳防止核颗粒烧结，并可能提供额外的催化功能。因此，对于费托合成（FTS），如果在FTS过程中产生的长链烃在多孔壳内的酸性位点裂解，壳提供了缩小产物选择性的可能性。该项目的目的是合成和表征用于在单个催化剂颗粒内组合FTS和加氢处理（HP）的双功能纳米结构催化剂。这些材料应该由嵌入沸石壳内的钴纳米颗粒组成。多孔壳应该能够使反应物在核和流体本体之间扩散，以及为HP提供催化功能。该材料的尺寸不应超过1 µm，以便命名为纳米结构，并能够在传统和微结构反应器中灵活应用。关键创新在于合成纳米结构双功能催化剂的新策略。关键的一点是从核心颗粒开始逐步构建材料，随后由具有定制特性的外壳覆盖。这种方法允许材料形态的高度可控性。主要的挑战是纳米尺度的复合材料的尺寸，这比双功能催化剂的最新技术水平小得多。该项目的实际状况证明了这一概念的可行性，并提供了第一个有希望的结果。这是可能的嵌入钴纳米粒子内的沸石基质。该材料在FTS中显示出显著活性。此外，产品组成的改变证实了材料在HP中的活性。

The objective of the project is the development of a novel method for combination of different functionalities within one catalytic material. The basis are nanometer sized core-shell materials, which are currently discussed as high temperature stable catalysts. For the application in heterogeneous catalysis these materials consist of a catalytically active core and a porous shell. The shell prevents the core-particles from sintering and might provide an additional catalytic functionality. For Fischer-Tropsch synthesis (FTS) the shell thus offers the possibility to narrow the product selectivity, if the long chain hydrocarbons produced during FTS are cracked at acidic sites within the porous shell.The aim of the project is the synthesis and characterization of bi-functional, nanostructured catalysts for the combination of FTS and hydroprocessing (HP) within one single catalyst particle. The materials are supposed to consist of a cobalt nanoparticle embedded within a zeolitic shell. The porous shell should enable the diffusion of reactants between the core and the fluid bulk, as well as provide a catalytic function for HP. The size of the material should not exceed 1 µm in order to be named nanostructured, as well as to enable flexible application within conventional and microstructured reactors.The key innovation is the novel strategy for synthesis of nanostructured, bi-functional catalysts. The crucial point is the step-wise construction of the material starting with the core particle, which is subsequently coved by shell with tailored properties. This approach allows a high degree of controllability of the material morphology. The main challenge is the dimension of the composite materials in the nanometer scale, which is considerably smaller than the state of the art of bi-functional catalysts.The actual status of the project demonstrates the feasibility of the concept and provides first promising results. It was possible to embed cobalt nanoparticles within a zeolitic matrix. This material was shown to be significantly active in FTS. Furthermore, the modification of the product composition confirms the activity of the material in HP.