To reveal the richer chemistry of CO oxidation by CeO2 supported Au Nanoclusters (NCs)/Nanoparticles, we design Au13 and Au12 supported on a flat and a stepped-CeO2 model (Au/CeO2) and study various kinds of CO oxidation mechanisms at the Au-CeO2 interface and the Au NC as well.1-3DFT+U calculations show that the surface of the Au NCs is mostly covered by CO molecules preventing CO oxidation by Au NCs whereas the Au-CeO2 interface facilitates CO oxidation. In the presence of the reduced Ce3+ ions, the Au-Ce3+ interface binds and activates O2 molecule for further oxidation of CO bound to Au NCs (Au-CO*). Otherwise, lattice oxygen at the CeO2 step edge oxidizes Au-CO* by the Mars- van Krevelen mechanism. CO2 desorption determines the rate of CO oxidation and the vacancy formation energy (Evac) is a reactivity descriptor for CO oxidation. The maximum Evac that insures spontaneous CO2 production is higher for the Au/CeO2-step than the Au/CeO2-surface suggesting that the CeO2-step is a better supporting material than the CeO2-surface for CO oxidation by the Au/CeO2.Our results suggest that for CO oxidation by Au NCs supported on nano- or meso-structured CeO2, which is the case of industrial catalysts, interface-mediated mechanisms account for a large portion of the total activity. (1)        Kim, H. Y.; Lee, H. M.; Henkelman, G. CO Oxidation Mechanism on CeO2-Supported Au Nanoparticles. J. Am. Chem. Soc. 2012 , 134, 1560-1570.(2)        Kim, H. Y.; Henkelman, G. CO Oxidation at the Interface of Au Nanoclusters and the Stepped-CeO2(111) Surface by the Mars�van Krevelen Mechanism. J. Phys. Chem. Lett. 2013 , 4, 216-221.(3)        Kim, H. Y.; Henkelman, G. CO Oxidation at the Interface between Doped CeO2 and Supported Au Nanoclusters. J. Phys. Chem. Lett. 2012 , 3, 2194-2199.Work supported in part by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with theU.S. Department of Energy.

CO Oxidation mechanism on CeO<sub>2</sub>-supported Au nanoclusters

246th National Meeting (2013)

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CO Oxidation mechanism on CeO2-supported Au nanoclusters

CO Oxidation mechanism on CeO₂-supported Au nanoclusters