The direct photoepoxidation of propene over binary TiO2-SiO2 catalysts holds the potential to selectively produce propene oxide under mild conditions without the use of sacrificial reactants. Recently, single atom Ti sites dispersed on an SiO2 support have been shown to selectively convert propene into propene oxide in the prescence of UV light and O2. In the current study, in situ infrared spectroscopy was utilized to track the molecular-level details of propene and propene oxide adsorption, diffusion, and reaction on a model TiO2-SiO2 binary catalyst. Specifically, a high flux LED light source irradiated the TiO2-SiO2 sample during the adsorption of oxygen and propene while infrared light probed the adsorbate-surface vibrational modes as the reaction progressed. Identification of surface-bound intermediates and products revealed key steps in the epoxidation reaction. With these discoveries, new mechanistic insight has been gained into the role that surface oxyradicals have on propene coordination and the overall photoepoxidation reaction.

Infrared spectroscopic studies of propene and propene oxide uptake, binding, and reactivity on TiO2-SiO2 binary catalysts

254th National Meeting (2017)

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