 Bruce C. Gates has been a professor of chemical engineering at the University of California, Davis since 1992. Previously, he was the H. Rodney Sharp Professor of Chemical Engineering, a professor of chemistry, and the director of the Center for Catalytic Science and Technology at the University of Delaware. He also worked as a research engineer at Chevron Research Company for two years following a postdoctoral appointment at the University of Munich’s Institute of Physical Chemistry, where he has returned numerous times as a visiting professor. Dr. Gates received his B.S. and Ph.D. degrees in chemical engineering from the University of California, Berkeley in 1961 and the University of Washington, Seattle in 1966.
Dr. Gates’s research is focused on catalysis, nanomaterials, and chemical reaction engineering. He has made contributions to catalytic hydroprocessing, catalysis by solid acids, and catalysis by supported metal complexes and metal clusters. He wrote the textbook Catalytic Chemistry and coauthored the textbook Chemistry of Catalytic Processes. He edits Advances in Catalysis and serves as a member of the Department of Energy’s (DOE) Basic Energy Sciences Advisory Committee and is on the Board of Directors of the North American Catalysis Society. He recently co-chaired a DOE Workshop entitled “Basic Research Needs in Catalysis for Energy.”
Among other achievements, Dr. Gates was elected to the National Academy of Engineering in 2007 for scholarship on catalysis, innovative research on hydroprocessing and supported molecular catalysts, and exemplary leadership in collaborative university/industry research.
(Visit Dr. Gates' web site for additional information about his research.) |
Hurry Up!
Accelerating Chemical Transformations with Catalysts
Wednesday, April 2, 2008 • 4:00 p.m. • MS&E Building • Room G011
Among the savory and pivotal words in our language, “catalyst” stands out across literature. Most people use “catalyst” to mean initiator or facilitator, but the scientific meaning is stronger — almost evoking an idea of something for nothing, like the philosopher’s stone sought by the alchemists. A catalyst makes chemical change go (really, go faster), and the catalyst is not even consumed in the process. No wonder that catalysts are the keys to controlling chemical change in life and in technology.
Nature’s catalysts are large, complex, intricately assembled molecules, called enzymes, that work in dilute biological soups and at body temperature. Catalysts invented by humans range from molecules and ions in solution to messy, nonuniform solids that are robust enough for use at high temperatures. Small components of these solids are located on surfaces and work elegantly but are difficult to understand. Catalysts are the essential facilitators of technology for chemical change ranging from manufacture of chemicals, fuels, materials, phamaceuticals, and foods to abatement of pollutants such as automobile exhaust. Catalysts will be the keys to future technology for renewable energy and environmental protection.
We will examine some catalysts, what they do, how they work, and how scientists and engineers discover, understand, and apply them.
Molecular Catalysis on Surfaces
Thursday, April 3, 2008 • 11:00 a.m. • Ford ES&T Building • Room L1255
Most industrial catalysts are robust solids that operate at high temperatures, and the challenge of understanding and predicting their behavior is complex because of the nonuniformity of their surfaces. But many industrial catalysts are uniform molecular species used at relatively low temperatures in solution, and these are generally much better understood than solid catalysts, as well as being more selective in the reactions they catalyze.
One can combine some of the benefits of both solid and molecular catalysts by synthesizing nearly uniform catalytic sites on solid surfaces. Such catalysts offer unique opportunities for fundamental understanding because the uniformity of structure facilitates incisive characterization of the catalytic species. Our goals were to synthesize a family of such catalysts consisting of transition metal complexes or clusters on supports and to investigate them with a set of complementary experimental methods as they functioned. The methods include vibrational, NMR, and X-ray absorption spectroscopies; high-resolution transmission electron microscopy; and density functional theory (DFT). The results determine catalyst structures including bonding of the metals to the supports and identification of reaction intermediates.
Results are presented for complexes of rhodium, iridium, and ruthenium on oxides and zeolites and for clusters of rhenium, rhodium, iridium, and osmium on these supports. For example, complexes of rhodium bonded to ultrastable Y zeolite were prepared from the precursor Rh(C2H4)2(C5H7O2), giving supported Rh(C2H4)2 complexes with each Rh atom bonded to two oxygen atoms of the zeolite. 13C NMR data demonstrate a uniformity of the supported species nearly matching that of the precursor in the crystalline state.
When the ethylene ligands on the supported rhodium complex were replaced by acetylene, catalytic cyclotrimerization to benzene ensued. Spectroscopic data provided evidence of the structures of intermediates in the catalytic cycle, and with these as anchors, we used density functional theory to elucidate the full catalytic cycle, including transition states.
Highly dispersed metal catalysts containing supported clusters of only several metal atoms each [e.g., Ir4, Ir6, and Rh6] were prepared by removal of CO ligands from supported precursors [e.g., Ir4(CO)12, Ir6(CO)16, and Rh6(CO)16]. Characterization of the supported clusters by EXAFS spectroscopy and DFT indicates metal-support oxygen bonds and the presence of cations of the metal at the metal–support interface, helping to stabilize the dispersion of the metals. The supported clusters are not bare; rather, they are stabilized by ligands such as hydrides formed from support OH groups by reverse hydrogen spillover.
Supported molecular catalysts are an emerging class of material that offers new reactivities and catalytic properties. Some of the lessons emerging from understanding of their structure, bonding, and reactivity appear to pertain to supported metal catalysts generally. |
About the Ashton Cary Lecture
 The Cary Lecture Series in the School of Chemical & Biomolecular Engineering was established in 1984 as a memorial to Ashton Hall Cary, a chemical engineering graduate of Georgia Tech, Class of 1943. Mr. Cary served in the U.S. Army after graduation and later built a career in Georgia’s textile industry. He was a native of LaGrange, Georgia, where he was prominent in local politics and business and active in many charitable and civic organizations. At the time of his death in 1983, Mr. Cary was a production consultant for Kleen-Tex Industries.
The Cary Lecture Series was initiated with a gift from Dr. Freeman Cary, who also studied chemical engineering at Tech. Dr. Cary, who is Ashton’s brother, received his M.D. from Emory University in 1950 and later became the attending physician for the U.S. Congress.The Cary Lectureship Fund is used to sponsor a lecture series by distinguished scholars in fields of significance to chemical engineering. The visiting lecturers, in addition to presenting seminars on recent engineering advances, participate in informal discussions with Georgia Tech faculty and students.
The Cary Family
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Nathan S. Lewis, 2007
Julia S. Higgins, 2006
Gregory Stephanopoulos, 2004
Richard M. Gross, 2003
Ignacio E. Grossman, 2002
Eric W. Kaler, 2001
Daniel I. C. Wang, 2000
John M. Prausnitz, 1999
Pablo G. Debenedetti, 1998
Donald R. Paul, 1997
Joseph A. Miller, Jr., 1996
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Gregory J. McRae, 1995
Stanley I. Sandler, 1994
L. Louis Hegedus, 1993
Matthew Tirrell, 1992
Robert S. Langer, 1991
Manfred Morari, 1990
C. Judson King, 1989
Octave Levenspiel, 1988
Giovanni Astarita, 1987
Edward E. David, Jr., 1986
Ilya Prigogine, 1985 |
