Lyman Handy Colloquium

SpeakerProf. Horia Metiu
Department of Chemistry and Biochemistry
University of California, Santa Barbara Abstract "Doped oxides as catalysts, why gold clusters are reactive, and electronic
manipulation of catalysis" I will talk about three distinct subjects, all connected to catalysis. In the first I will explore whether doped oxides (for example, AuxCe1-xO2) might provide us with a new class of oxidation catalysts. We do this by using density functional calculations, to determine the binding energies of various compounds and the activation energies of the possible reactions. We use CO oxidation as a test of the oxidizing power of the doped oxides. In the second topic I discuss experiments done in collaboration with Moskovits and Kolmakov in which we test whether manipulating the number of electrons in a nano-catalyst can affect the catalytic activity. The experiments study CO oxidation by a SnO2 nanowire, which is part of an electric circuit and sits on top of a gate. We find that we can manipulate the reaction rate by changing (with the gate) the number of electrons in the wire. Finally, if there is any time left I will discuss a possible reason why small Au clusters are good catalysts, while large clusters are not. We and others have proposed that the clusters are reactive because they have many low coordination sites on the surface. Here I want to amend that picture and propose that the reactivity depends on what I call "orbital roughness", not on geometrical (low coordination) roughness.

Audiences: Everyone Is Invited

Contact: Petra Pearce