This talk will describe some of our recent efforts to better understand the roles of water and the underlying support in affecting benzyl alcohol oxidation catalysis by supported Au nanoparticles.  In particular, we have applied a Michaelis-Menten approach to examining kinetic data that allows us to consider differences in the number of reactive molecules from their inherent activity. A series of drying studies indicated that water promotes benzyl alcohol oxidation, and prompted the suggestion of a slightly modified mechanism from the literature.  In this new proposed mechanism, we suggest that the alcohol adsorbs onto the support, followed by proton transfer from the alcohol to generate an active alkoxide at the metal-support interface.  The relative number of these active alkoxides near the Au nanoparticle was associated with the number of reaction centers on the catalyst. <br/><br/>The kinetic data was well described by this model, which provided an important framework for considering the differences in activity between the catalysts.  Double reciprocal plots indicated that differences in reactivity could be attributed to fundamental differences in the rate constant for hydride transfer from the benzylic carbon to Au, rather than to differences in the number of active sites from one catalyst to another.  This conclusion is further supported by intentional poisoning experiments.  Further, both experimental and computational Hammett studies indicate that the support plays an important role in tuning the surface electronics of Au nanoparticle catalysts. <br/>

Mechanistic studies of benzyl alcohol oxidation to probing changes to the active site in supported Au catalysts: Support effects and proton shuttling

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.