Supported Au catalysts have been shown to be effective in selective oxidation of propane to acetone.  Interestingly, the selectivity depends strongly on the support: Au supported on TiO2 yields propene, whereas Au supported on TS-1 yields acetone.  When coupled with the recent report that Au-titania interface appears to be essential for low temperature CO oxidation, it appears that an active site composed of a Au-oxotitanium entity may be essential for activation of oxygen for selective oxygenate formation.  We examined the role of such an entity in acetone formation in propane oxidation by generating these entities with functionalized siloxane oligomers.  Siloxane oligomers can be functionalized with amine and titanyl ligands of controlled stoichiometry.  Since the amine ligands can stabilize Au nanoparticles, it is possible to vary systematically the density of titanyl ligands associated with the Au particles.  By varying the deposition sequence of Au particles and functionalized siloxane oligomers, it is possible to vary the separation distance of Au and titanyl groups.  By comparing the acetone yields from these samples, it is possible to deduce the role of Au-titanyl entity in the reaction.  Results of this study will be presented.

Role of TiOx in Au catalyzed propane oxidation

243rd National Meeting (2012)

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