Interfacial design of function integrated catalysts for ethanol dehydrogenation

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The project aims in a prototypical manner at the development of nanostructured catalysts for the dehydrogenation of ethanol. It relies on controlled formation and modification of interfaces between support and copper as the active phase. This should solve two problems, with the solution starting from the knowledge available for the system. Silica as support stabilizes copper nanoparticles very well, due to the formation of oxobridges between copper and support. On the other hand, silanol groups on the silica lead to side reaction, which reduce the selectivity to acetaldehyde. Carbon is an alternative support with reduced side reactions, but the copper particles are only weakly anchored, so that such systems are susceptible to sintering.These problems shall be solved by a designed interface. First, silica will be coated with a thin carbon layer, which suppresses the side reactions. Then copper nanoparticles will be deposited. Thermal treatement in hydrogen leads to local methanization of the carbon, so that the copper particles move through the carbon layer to the silica surface, where they are tightly anchored.Such catalysts are probably not easy to regenerate, since oxidative treatment will destroy the carbon layer. Therefore, two alternative concepts shall also be studied. The first uses SiC as support, the surface of which can be modified with different types of defects by controlled treatment. Copper can be anchored to these defects and thus efficiently immobilized, but due to the different surface functionalities compared to silica, side reactions may possibly be suppressed. The second system relies on arrays of oxide nanotubes, which have recently been synthesized for the first time. These tubes can be made from zirconia, with diameters on the order of 3 nm. In the tubes, copper nanoparticles will be immobilized, with the oxygen atoms being close to the copper sites, due to the small diameters. This is connected with high acetaldehyde selectivity of the catalyst.The catalysts will be characterized in ethanol dehydrogenation with respect to activity and selectivity. The properties of the catalysts will comprehensively be characterized ex-situ and under reaction conditions in order to correlate the tailored interface properties to the catalytic properties, which serves to improve the catalysts further.While the work is focussed on the title reaction, it will probably be possible to generalize the concepts to be developed to other systems. It is therefore hoped that the study will provide a blueprint for the knowledge-based development of nanostructured catalysts.