Frontiers in Catalysis Science and Engineering
Dr. Stefan Vajda
Dr. Stefan Vajda
Argonne National Laboratory
Chemical Sciences and Engineering
"Bond-Selective Chemistry on Catalysts Designed
at the Subnanometer to the Nanometer Scale"
Tuesday, September 8, 2009
EMSL/Auditorium
1:00 PM - 2:00 PM
» Research Highlight: Small, Smaller, Smallest
The elucidation of the correlation between the size/composition/shape of a catalyst and its function are instrumental on the way to the design of new classes of catalytic materials. Highly uniform particles on technologically relevant supports are prerequisites for such studies.
The experimental studies are based on 1) chemically uniform support fabrication, 2) size-selected cluster deposition, 3) electron microscopy of nanoclusters, and 4) in situ synchrotron X-ray characterization of clusters under working conditions, combined with mass spectroscopy analysis of reaction products.
1) Selective activation of the C=C bond in propene to form propylene oxide on alumina supported Ag nanoparticles and clusters. The size-dependent activity and selectivity of Ag nanoparticles will be compared with the performance of sub-nanometer Ag3 and Au6-10 clusters. The subnanometer gold catalyst performs without the commonly used TiO2 support and hydrogen additive.
2) Selective dehydrogenation of propane on Pt8-10 clusters. Pt clusters on mesoporous membranes identify the first viable Pt-based catalyst composition which, while the most selective under oxidative conditions, outperforms by a factor of 40 to 100 the activity of the best reported Pt-based and VOx-based catalysts, respectively.
3) As time will allow, methanation & Fischer-Tropsch reactions on size-selected nickel and cobalt clusters are chosen to illustrate the recent addition of simultaneous X-ray absorption to the temperature-programmed reaction & X-ray scattering approach. Pronounced size, composition and support effects on catalyst performance are observed.
Prof. Dr. Jean-Pierre GilsonProf. Dr. Jean-Pierre Gilson
Director, Laboratoire Catalyse & Spectrochimie
Caen, France
"New Insights on Zeolite Chemistry by Advanced IR and NMR Characterization Tools"
Tuesday, June 23, 2009
EMSL Auditorium
10:00 AM - 11:00 AM
Research Highlight: Teaching Catalysts to Play Ball
New techniques and methodologies in the spectroscopic characterization of zeolites are yielding new insights in the complexity of zeolitic materials. In particular, emerging IR and NMR techniques shed new lights on old problems such as acidity. New, rich, and quantitative information can be gathered. In particular, the ability to work under the operando conditions yields much valuable data to rationally design better catalysts or zeolite-based materials. The following points will be discussed:
- Accessibility of active (acid) sites
- Size & basicity: the problem of substituted pyridines
- Confinement & basicity: Acetonitrile in Si-MOR
- Quantifying the IR signal of adsorbed molecules
- IR operando spectroscopy
- HP 129Xe NMR.
Dr. Marc J.A. Johnson
University of Michigan
"Tuning the Strength and Reactivity of Metal-Ligand Bonds: Reactive Nitrides and Stable Carbides in Catalytic Multiple-Bond Metathesis Reactions"
Tuesday, March 31, 2009
EMSL Auditorium
10:00 AM - 11:00 AM
Modification of the ancillary ligand set can be used to tune the relative strength of metal-element multiple bonds rationally. New nitride complexes of Mo and W that are activated toward triple bond metathesis are described. In the case of W, pairwise nitride/alkylidyne exchange can be reversible, leading to a new catalytic reaction, nitrile-alkyne metathesis.
Speakers have included:
Prof. Dr. Johannes Lercher
Technischen Universitat Munchen
"Catalytic activation of hydrocarbons in confined spaces"
Tuesday, August 26, 2008
EMSL Auditorium
10:00 AM - 11:00 AM
The lecture addresses the elementary steps involved in the conversion of hydrocarbons at acid sites in well-defined environments. These steps include, transport to and sorption on sites in and outside the pores, the addition of protons and the abstraction of hydrogen as initiating steps, the surface reaction and finally the desorption of the products.
Prof. Dr. Cynthia M. Friend
Harvard University
"Chemical reactivity and surface restructuring at the nanoscale: Oxidation reactions promoted by Au"
Tuesday, March 18, 2008
EMSL Auditorium
9:30 AM 10:30 AM
Due to the catalytic importance of oxidation reactions at low temperature, Au is under intense investigation as a component in low-temperature catalysts since Haruta discovered that Au nanoparticles are active for these processes.
Prof. Dr. Peter C. Stair
Northwestern University and Argonne National Laboratory
"The chemical nature of supported vanadium oxide"
Wednesday, January 30, 2008
EMSL Auditorium
2:00 PM 3:00 PM
Vanadium oxide supported on alumina, silica, titania, zirconia, and other oxides is one of the most extensively studied catalyst materials. The catalytic performance of supported vanadia has been investigated for a variety of hydrocarbon transformations, especially the oxidative dehydrogenation of alkanes and the oxidation of methanol in order to establish the relationship between the chemical, physical, and structural nature of supported vanadia and its catalytic function.
