Events & Seminars > Event Details

Where:

4:00pm
Room 304, Chemistry Building

Discovery of a New Type of Catalytic Site Involving Nano-Gold Particles

Speaker:

Professor John T. Yates, Jr.
University of Virginia

Hosted by: Professor Matt Neurock

     Just two years ago, Izzie Green, working in my group in Chemistry at UVa, along with Matt Neurock and Wenjie Tang in Chemical Engineering, discovered a new type of catalytic site involving ~ 3nm diameter Au particles supported on TiO2[1,2].  This site has the remarkable property of catalyzing the oxidation of a variety of molecules at low temperatures with low activation energies. The site is located along the perimeter of the supported Au nanoparticles at the interface where the Au joins the TiO2 support. O2 molecules, bound on one end by a Au atom and on the other end by a Ti4+ site, are activated by charge transfer from the dual catalytic site and dissociate to O atoms which are then very active as oxidizing agents. Probes leading to this surprising model of the catalytic site employed transmission IR spectroscopy, chemical kinetics and density functional theory. Monica McEntee has now studied this site in the ethylene oxidation reaction finding that ethylene oxide, an expected product, is not produced- instead ethylene cleanly oxidizes to acetic acid and beyond. A new rather exotic oxidation product, ketenylidene, Au2=C=C=O, is also observed [3, 4] as acetic acid is oxidized further.  

Work supported by DOE and by Fellowship Grants to both Izzie Green and Monica McEntee by the AES Corporation.

[1]. I. Green, W. Tang, M. Neurock and J. T. Yates, Jr., Science, 333, 737 (2011).

[2]. I. Green, W. Tang, M. Neurock and J. T. Yates, Jr., J. Amer. Chem. Soc., 134, 13569, (2012).

[3]. I. Green, M. McEntee, W. Tang, M. Neurock and J. T. Yates, Jr., Topics in Catalysis, in press.

 

Dual catalytic site involving Au atoms and Ti4+ sites which possess extraordinary activity for oxidation reactions.