2024 Ensor Lectureship
Mark A. Barteau is a Professor in the Departments of Chemical Engineering and Chemistry at Texas A&M University, where he holds the Charles D. Holland ‘53 Chair and previously served as the Vice President for Research. He was the Director of the University of Michigan Energy Institute from 2012 to 2018. Prior to that, he was the Senior Vice Provost for Research and Strategic Initiatives at the University of Delaware, where he held appointments as the Robert L. Pigford Endowed Chair of Chemical Engineering and Professor of Chemistry & Biochemistry. He was elected to the National Academy of Engineering in 2006, and the National Academy of Inventors in 2018. He received his B.S. degree in Chemical Engineering from Washington University in St. Louis, and his M.S. and Ph.D. from Stanford. He was an NSF Post-doctoral Fellow at the Technische Universität München, before joining the University of Delaware faculty in 1982. His research, presented in more than 250 publications and a similar number of invited lectures, focuses on chemical reactions at solid surfaces and their applications in heterogeneous catalysis and energy processes. He has also contributed perspectives on energy, environment, economics, and policy to The Conversation, Fortune, The Hill, and NPR, among other media outlets.
Dr. Barteau was named in 2008 as one of the “100 Engineers of the Modern Era” by the American Institute of Chemical Engineers (AIChE). He is a fellow of both AIChE and the American Association for the Advancement of Science. He has received numerous awards, including the 2018 Lawrence K. Cecil Award in Environmental Chemical Engineering, the 2001 Alpha Chi Sigma Award, and the 1991 Allan P. Colburn Award, presented by AIChE; the 1998 International Catalysis Award, presented by the International Association of Catalysis Societies; the 1995 Ipatieff Prize from the American Chemical Society; the Paul H. Emmett Award in Fundamental Catalysis, given by the North American Catalysis Society, and the 1993 Canadian Catalysis Lecture Tour Award of the Catalysis Division of the Chemical Institute of Canada. He has served as associate editor of the AIChE Journal and WIRES Energy and Environment, and on the editorial boards of a number of other Journals, including Industrial & Engineering Chemistry Research and the Journal of Catalysis.
Lecture: A personal tour of surface acid-base chemistry and catalysis: from solution to the gas phase and back again
The description of oxygen atoms on metal surfaces as base sites in surface science studies emerged about 40 years ago. Since little water is present in the UHV environment, surface species are not solvated, and gas-phase acidities were shown to describe the behavior of organic acids and their conjugate bases better than did pKa values from aqueous solution. This implies that ligands such as carboxylates and alkoxides on metals such as silver have considerable anionic character. On metal oxide surfaces, however, the bond formed between these ligands and surface cations compensates for much of the energy of heterolytic dissociation of the parent acid, and the scale of relative acidities becomes compressed. Still, for competitive adsorption studies in vacuum, solvation is minimal and pKa values of adsorbates are not useful.
Catalytic reaction conditions may not be so dry, but the potential effects of solvation of surface species in nominally gas-solid reactions have largely been ignored until recently. Our studies of cation exchange effects on the oxidation and dehydration of methanol with supported polyoxometalate catalysts suggest that surface acid sites are solvated under reaction conditions. Catalytic activity in these studies can be accounted for quantitatively by the Harned relation, which describes non-ideal behavior of highly concentrated acid solutions. These results suggest that the role of water, especially in catalytic processes where it may be an additive, a co-product, or both, may not be fully appreciated.