Two anatase titania model catalysts, with preferential exposure of (101) and (001) facets, were synthesized and studied for 2-propanol dehydration. A series of microscopic and spectroscopic techniques including XRD, SEM/TEM, NH3-TPD, DRIFTS and chemical titration were employed to correlate the structure properties of the model catalysts to their catalytic performances. Based on selective site poisoning titration using 2,6-di-tert-butyl pyridine, surface Lewis acid sites were found to be active for 2-propanol dehydration. The higher activity for TiO2 (101) catalyst was ascribed to its higher acid strength and density in comparison to TiO2 (001). Temperature-dependent DRIFTS were used to describe possible surface species under steady-state reaction conditions. Based on which, model surface structures were constructed on which 2-propanol dehydration was simulated with density functional theory. In both cases, 2-propanol was found to dehydrate via concerted E2 elimination pathways, but with different extents of surface O (or OH) participation. The results reported here clearly reveal faceting effects of metal oxides for alcohol dehydration and shed lights on catalytic oxygen removal for biomass-derived chemicals on metal oxide catalysts in general.

Single-facet dominant anatase TiO2 (101) and (001) model catalysts to elucidate the active sites for alkanol dehydration

256th National Meeting (2018)

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