Nanostructured Core-Shell-Catalysts for Fischer-Tropsch Synthesis

点击翻译按钮获取中文摘要

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.