(4de) Unravelling Structure-Activity Relationships of Heterogeneous Catalysts

As the world’s sources of energy and hydrocarbons evolve, much opportunity is created in the fields of catalysis and catalytic materials.  Several challenges for which I am particularly well-positioned to make important advancements include the following:  developing fundamental understanding of selective removal of heteroatoms from hydrocarbons found in feedstocks such as shale, coal and biomass; elucidating structure-activity relationships for reactant adsorption and conversion via in-situ catalytic and spectroscopic characterization; synthesizing catalytic materials, including zeolites and enzyme-inspired supported-organometallic clusters, to advance the understanding of structure-activity relationships.  Data such as these will lead to the development of catalysts and processes for the conversion of new energy and chemical feedstocks.

As a post-doctoral researcher at University of California—Berkeley, in conjunction with Dr. Alexander Katz and Dr. Stacey Zones, I am elucidating structure-activity relationships for new classes of catalytic materials—delaminated zeolites and supported metallocalixarenes—by using probe reactions.  Mild delamination of layered zeolites, which retain high structural integrity and have acid sites available to bulky molecules, is expected to expand the range of molecules useable for zeolite-catalyzed reactions.  Supported metallocalixarenes comprise bulky ligands on metal clusters to facilitate stability, allow access by small molecules, and create tunable metal catalysts by varying ligand electron donating or withdrawing properties.  The supported enzyme-like cluster catalysts are characterized in-situ via catalysis, spectroscopic, and isotopic exchange experiments to determine structure-activity relationships.  The combination of synthesis (by which the structure of the catalyst can be modified) and catalysis gives me tools to better elucidate fundamental understanding in the adsorption and catalytic conversion of new feedstock molecules.

My thesis work at the University of California—Davis, in conjunction with Dr. Bruce Gates and Dr. David Block, focused on developing a fundamental understanding of the catalytic conversion of lignin-derived compounds to fuels.  Most researchers had focused on the conversion of sugars and polyols from cellulose degradation, and left the conversion of nearly 30 wt% of biomass—lignin—untouched.  Our goal was to determine such a detailed reaction network for compounds representative of lignin-derived bio-oils and an important functional group characterizing compounds in them.  Data characterizing these reactions determined conversions and yields of products, including trace products; an approximate reaction network for each reactant and generalization of the results to reactant types and reaction classes; conversion data sufficient to approximately quantify kinetics of the principal reactions in the networks.  The data provide understanding to allow resolution of the roles of the separate catalyst functionalities (e.g. solid acid and metal) and provide a basis for prediction of reactivities of whole bio-oils.  This research area was new for Professors Gates and Block.  As a result, I now have experience in starting up an academic research lab including designing and constructing laboratory process equipment necessary for my research.

Future work will build upon my expertise in catalyst synthesis of zeolites and supported enzyme-inspired organometallic clusters and in heterogeneous catalysis to develop fundamental understanding of structure-activity relationships for the formation of useful chemicals and fuels and to provide a basis for understanding more complicated systems.