Seminar: Surface Chemistry on Nanoparticles: Size, Structure, and Electronic Effects

Nanoparticles by Design Unit (Sowwan Unit) would like to invite you to a seminar  by Prof. Scott L Anderson from Chemistry Department University of Utah.

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Date:   Tuesday, June 13, 2017  

Time:   14:00 – 15:00

Venue: Meeting Room C015, Level C, Lab 1

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Title: Surface Chemistry on Nanoparticles:  Size, Structure, and Electronic Effects

Speaker: Prof. Scott L Anderson

Affiliation: Chemistry Department/University of Utah

Abstract:

The surface chemistry of small metal nanoparticles can be substantially different than that observed for bulk metal or larger nanoparticles, due to differences in the availability of particular binding sites, and quantum confinement effects on electronic structure.  Two approaches to probing size effects will be discussed.  For very small particles, in the cluster size regime, it is practical to prepare atomically monodisperse beams of cluster ions, which we deposit on well characterized surfaces and study by surface science or electrochemical techniques.  We have recently developed methods to selectively alloy or dope size-selected, deposited clusters and are examining these bimetallic systems.  Examples of both electronic and geometric site effects on catalysis will be presented, and the results are shown to have important implications for spectroscopic studies of nanometer structures.

            For larger particles, with thousands-to-millions of atoms, the size selection approach becomes impractical, but single particle techniques can be used instead.  A single particle is trapped, and then its optical/near-IR emission spectrum and mass are measured non-destructively to high precision while the particle is heated and/or exposed to gaseous reactants.  The kinetics of surface reactions can be measured with high sensitivity by tracking the mass.  By carrying out measurements on a series of particles, the effects of particle size are determined, and titration methods can be used to enumerate the number of different kinds of surface sites, for correlation with reaction rates.  Oxidation and sublimation chemistry of carbon nanoparticles will be used to illustrate the method.

Biography:

Scott L. Anderson received a B.A. in Chemistry from Rice University in 1977, a Ph.D. from UC Berkeley in 1981, and then did postdoctoral work at Stanford.  He joined the chemistry faculty at Stony Brook in 1983, and moved to the University of Utah in 1995, where he is currently Distinguished Professor of Chemistry.  His early research work focused on gas-phase processes, including vibrational and electronic effects on reaction dynamics, gas-phase cluster chemistry, soft x-ray photochemistry, fullerene scattering dynamics, and combustion chemistry.  His current work is broadly in the area of nanoscale surface chemistry, including size effects in supported catalysts and electrocatalysts, single particle mass spectrometry for nanoparticle optical and surface chemistry characterization, use of surface-ligand interactions to control nanoparticle production and chemical properties, and methods for characterization of surface-modified nanoparticles.  He recently won the 2016 ACS Physical Division Award in Experimental Physical Chemistry.  He is a fellow of the American Physical Society and the American Association for the Advancement of Science, is vice-chair of the Division of Chemical Physics of the American Physical Society, Associate Director of the Utah Nanofab for Surface Analysis and Nanoimaging, and is on the editorial advisory boards for Surface Science, and Accounts of Chemical Research.