Helena Hagelin-WeaverAssociate Professor and Ph.D. Recruitment Coordinator
WE WORK ON HETEROGENEOUS CATALYST DEVELOPMENT in my laboratory and our ultimate goal is to obtain a fundamental understanding of these catalysts at the atomic level. Our approach is to synthesize well-defined heterogeneous catalysts using nanoparticle oxides with various shapes and sizes as supports and use different methods, including conventional precipitation deposition and incipient wetness impregnation as well as atomic layer deposition, to deposit active metals onto these supports. Since different shapes of nanoparticle oxides expose different surface facets, the use of these materials allows us to investigate how the active metal-support interactions vary with surface facets, and how this ultimately affects the catalytic activities and selectivities. Furthermore, the fraction of coordinatively unsaturated corner and edge sites (relative to terrace sites) increases with decreasing particle size. Therefore, by varying the size of the nanoparticle oxides, the effects of coordinatively unsaturated sites on the active metal can be investigated. The use of atomic layer deposition of metal (or metal oxide) onto these nanoparticle oxides can provide better control over the metal particle size on the support.
OUR RESEARCH INVOLVES CAREFUL CHARACTERIZATION OF the synthesized heterogeneous catalysts using a number of analytical techniques to determine important catalyst properties. We routinely perform surface area measurements, chemisorption of selected molecules to probe specific sites, temperature programmed reduction and oxidation (TPR and TPO) experiments to determine reduction-oxidation (redox) properties, X-ray diffraction (XRD) measurements to determine crystal structures and crystallite sizes, X-ray photoelectron spectroscopy (XPS) to determine electronic structure and surface chemical composition, high-resolution transmission electron microscopy (TEM) to determine particle sizes and shapes, and use the information to determine structure-activity relationships.
WE FOCUS MAINLY ON ENVIRONMENTALLY FRIENDLY, ENERGY-RELATED REACTIONS
Our projects include catalyst development for selective oxidation and hydrogenation reactions. Examples include oxidative coupling of methane (methane to higher-value chemicals), selective hydrogenations for parahydrogen-induced polarization nuclear magnetic resonance applications, and thermochemical water-splitting using solar energy.
Ph.D., 1999, Royal Institute of Stockholm, Sweden
- Luke M. Neal, Michael L. Everett, Gar B. Hoflund, Helena E. Hagelin-Weaver, “Characterization of Palladium Oxide Catalysts Supported on Nanoparticle Metal Oxides for the Oxidative Coupling of 4-Methylpyridine,” J. Mol. Catal. A 335 (2011) 210-221.
- Samuel D. Jones, Luke M. Neal, Michael L. Everett, Gar B. Hoflund, Helena E. Hagelin-Weaver, “Characterization of ZrO2-promoted Cu/ZnO/nano-Al2O3 methanol steam reforming catalysts,” Appl. Surf. Sci. 256 (2010) 7345-7353.
- Luke M. Neal, Samuel D. Jones, Michael L. Everett, Gar B. Hoflund, Helena E. Hagelin-Weaver, “Characterization of alumina-supported palladium oxide catalysts used in the oxidative coupling of 4-methylpyridine,” J. Mol. Catal. A 325 (2010) 25-35.
- Samuel D. Jones, Helena E. Hagelin-Weaver, “Steam reforming of methanol over CeO2- and ZrO2-promoted Cu-ZnO catalysts supported on nanoparticle Al2O3,” Appl. Catal. B 90 (2009) 195-204.
- Luke M. Neal, Daniel Hernandez, Helena E. Hagelin-Weaver, “Effects of nanoparticle and porous metal oxide supports on the activity of palladium catalysts in the oxidative coupling of 4-methylpyridine,” J. Mol. Catal. A 307 (2009) 29-36.