Henry Prentiss Becton Professor of Engineering and Applied Science
ChE & EnvE Engineering & Chemistry
Member of Yale faculty since 1967
Research The goal of our research has been to understand and rationalize heterogeneous catalytic activity and selectivity in terms of surface or deduced site structure. Surface and/or site structure primarily requires spectroscopic characterization, but this is usually accompanied by physi- and chemisorption and model catalytic activity studies. We are currently investigating a variety of catalysts based on mesoporous molecular sieves of the MCM-41 structure. These are synthetic materials with a very uniform hexagonal array of non-intersecting tubular pores. They have the particular advantage that the pore size can be varied systematically in the range of about 1.5-4.5 nm (a range that can be extended to greater than 10 nm) and this is a range where the radius of curvature of the pore wall can affect physical and chemical properties such as the heat of physical adsorption and local bond angles around a site (which may affect the site activity).
In order to investigate the radius of curvature of pore walls on catalytic chemistry, it is first necessary to synthesize materials, which have a constant composition and degree of structural uniformity. Because there are very many synthesis parameters, it is necessary to develop quantitative synthesis models, which we have done for V-MCM-41, Co-MCM-41 and these are being extended to Ni-MCM-41.
We have discovered that we can use the radius of curvature (and other synthesis parameters) and partially reduce isomorphously substituted MCM-41, e.g., Co-MCM-41, to produce very high dispersions of the metal where the metal clusters can be varied in the subnanometer size range. Because Co is a good catalyst for the synthesis of single-wall carbon nanotubes and the diameter of the nanotubes is controlled by the Co cluster size on which the nanotube grows, this provides a method to choose the average diameter of the single-wall carbon nanaotube and to synthesize a very narrow distribution around this average. The single-wall carbon nanotubes are being studied for hydrogen storage and it is observed that the hydrogen storage properties are a function of the diameter of the nanotubes.
B.S. University of Nebraska, Kearney, 1962
Ph.D. Northwestern University, 1966
NATO Postdoctoral Fellow, Oxford University, 1966-67
Donald E. Fox Chemistry Lectureship, University of Nebraska, Kearney, 1982
Outstanding Alumni Award, University of Nebraska, Kearney, 1988
The George C.A. Schuit Lectureship, Center for Catalytic Science and Technology, University of Delaware, 1990
Catalysis Society of Metropolitan New York Award for Excellence in Catalysis, sponsored by Exxon Research and Engineering Compnay, 1993
Yale Science and Engineering Association Meritorious Service Award, 1995
Robert Burwell Lectureship, The Catalysis Society, sponsored by Amoco, 1995
Harry Fair Lectureship, University of Oklahoma, 1995
Ipatieff Lectureship, Northwestern University, 1996
Lacy Lectureer in Chemical Engineering, California Institure of Technology, 1996
NIOK (Neterlands Institeu for Catalysis Research), Lecturer (Guest Teacher), 1996
Professeur Invité à l'Université Pierre et Marie Curie (Paris VI), 1996
Y. Yang, G. Du, S. Lim, & G.L. Haller. Radius of curvature effect of V-MCM-41 probed by methanol oxidation. J. Catal. 2005, 234, 318-327.
G. Du, S. Lim, Y. Yang, C. Wang, L. Pfefferle, & G.L. Haller. Catalytic performance of vanadium incorporated MCM-41 catalysts for the partial oxidation of methane to formaldehyde. Appl. Catal. A. Gen. 2006, 302, 48-61.
G. Du, S. Lim, M. Pinault, C. Wang, F. Fang, L. Pfefferle, & G.L. Haller. Synthesis, characterization, and catalytic performance of highly dispersed vanadium grafted SBA-15 catalyst. J. Catal. 2008, 253, 74-90.
S. Lim, N. Li, F. Fang, M. Pinault, C. Zoican, C. Wang, F. Chuan; T. Fadel, L. D. Pfefferle, & G.L. Haller. High-Yield Single-Walled Carbon Nanotubes Synthesized on the Small-Pore (C10) Co-MCM-41 Catalyst. J. Phys. Chem. C. 2008, 112, 12442-12454.
C. Wang, S. Lim, G. Du, C. Zoican Loebicki, N. Li, S. Derrouiche, & G.L. Haller. Synthesis, Characterization, and Catalytic Performance of Highly Dispersed Co-SBA-15. J. Phys. Chem. C. 2009, 113, 14863-14871.
X. Wang, N. Li, L.D. Pfefferle, & G.L. Haller. Pt-Co Bimetallic Catalyst Supported on Single-Walled Carbon Nanotubes: Effect of Alloy Formation and Oxygen Containing Groups. J. Phys. Chem. C. ACS ASAP.