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O: Fachverband Oberflächenphysik

O 81: Gerhard Ertl Young Investigator Award

O 81.2: Vortrag

Donnerstag, 19. März 2015, 11:00–11:30, MA 042

High Spatial Resolution Operando IR and X-ray Microspectroscopy Measurements of Multistep Catalytic Reactions in Flow Reactor — •Elad Gross — Institute of Chemistry, The Hebrew University of Jerusalem, Israel

Molecular-level analysis of catalytic reactions in flow reactors and detection of short lived intermediates are essential for optimization of complex reactions. In this study, multistep catalytic reaction in flow reactor was analyzed by spectral mapping of the catalyst and the organic phase with a spatial resolution of 15 μm, employing micrometer-sized synchrotron-sourced IR and X-ray beams. The catalyst in this reaction was two nanometer sized Au nanoclusters that were encapsulated within a dendrimer matrix and loaded on mesoporous SiO2 support. The catalyst was packed within a flow microreactor and its reactivity was tested toward the cascade reaction of dihydropyran formation. In-situ synchrotron-sourced IR microspectroscopy detected the reactant-into-product transformation along the flow reactor. By tuning the residence time of the reactants, full kinetic analysis of the catalytic reaction was achieved. X-ray absorption microspectroscopy scan along the flow reactor correlated locally-enhanced catalytic conversion, as detected by IR microspectroscopy, to areas with high concentration of Au(III), the catalytically active species. This study demonstrates the fundamental understanding of mechanism of catalytic reactions that can be gained by detailed in-situ mapping of multistep reactions in flow reactors.