Nanostructured gold model catalysts on thin film substrates William C. McKee,1 Matthew Patterson,2 Dali Huang,3 Li Liu,3 Richard Kurtz,2 Phillip Sprunger2, and Ye Xu1 1. Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803 2. Department of Physics and Astronomy and CAMD, Louisiana State University, Baton Rouge, LA 70803 3. Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843 Au nanoparticles exhibit remarkable catalytic properties, particularly for low-temperature and selective reactions.1-3 The precise role of Au, however, remains a subject of research even in simple reactions such as CO oxidation because of the potential involvement of the support material and reaction environment.4,5 We demonstrate that a monolayer hexagonal boron nitride (BN) film provides periodic sites for nucleation of monodisperse Au nanoparticles because it forms a long-range pore-wire superstructure when supported on Rh(111).6 Although the BN film is chemically inert, the resulting dense arrays of Au nanoparticles remain confined to the pore regions even at multi-layer Au coverages and on warming to room temperature. The system is characterized using a variety of methods, including scanning tunneling microscopy, X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and chemisorption of probe molecules such as CO, as well as density functional theory based modeling. The DFT calculations and experiments are in close agreement regarding the adsorption properties of CO on the Au nanoparticles. Evidence is found for charge transfer resulting in negatively charged Au nanoparticles, with the charge localized at periphery Au sites that are highly reactive toward CO chemisorption, causing the C-O stretching frequency to red-shift considerably. The Au/BN/Rh(111) system represents a potentially attractive model catalytic platform on which to study Au catalysis in the isolated Au limit. References 1. Haruta, Catal. Today 1997, 36, 153. 2. Meyer, Lemire, Shaikhutdinov, Freund, Gold Bull. 2004, 37, 72. 3. Corma, Garcia, Chem. Soc. Rev. 2008, 37, 2096. 4. Green, Tang, Neurock, Yates, Science 2011, 333, 736. 5. Saavedra, Doan, Pursell, Grabow, Chadler, Science 2014, 345, 1599. 6. Patterson, Habenicht, Kurtz, Liu, Xu, Sprunger, Phys. Rev. B 2014, 89, 205423.

Nanostructured gold model catalysts on thin film substrates

249th National Meeting (2015)

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