(6ic) Nano-Structured Catalysts for Clean Fuels and Chemicals: Directing Activity and Selectivity By Design

One of the ultimate goals of catalyst-related research efforts is the rational design of active, selective and stable catalytic materials. To this end, the rapid advancement of state-of-the-art characterization techniques (e.g. in-situ and operando electron microscopy and X-ray spectroscopies) provides new opportunities for identifying the critical properties of nanomaterials that drive various catalytic processes. My previous work on metal-based catalytic materials for clean fuel and green chemistry applications lies at the intersection of catalyst design, synthesis, testing, and characterization. This puts me in a unique position to apply powerful techniques to emerging challenges in catalyst development for today’s changing energy landscape. I will present my work on these topics and plans for future research.

My Ph.D. thesis focused on developing our understanding of alkali-promoted noble metal catalysts for alternative fuel production. The ability of alkali metals to promote the water-gas shift activity of platinum-based catalysts has been reported on a number of supports, although the nature of the active site remains controversial. Water activation is thought to be the rate-limiting step, making the surface hydroxyl concentration fundamentally linked to the reaction rate. The use of oxide-free (carbon) supports and state-of-the-art microscopy and spectroscopy techniques allowed us to confirm the stabilization of atomically dispersed Pt-OH_x species on Na-modified Pt catalysts. The approach for stabilizing such species has resulted in further development of promoted noble metal catalysts for the water-gas shift reaction.

My postdoctoral research aims to elucidate the nature of the interplay between Ag and Au in nanoporous gold architectures, which contain only dilute quantities of Ag. Ag is believed to act as a promoter that activates dioxygen, allowing for selective oxidation (e.g. esterification) reactions to take place with high (Au-like) selectivity. An activation procedure resulting stable catalyst activity was developed. With the use of in-situ spectroscopy and microscopy techniques, atomic-scale structural changes in the catalyst were related to activity and selectivity in alcohol coupling reactions. These principles can be used to design new catalyst formulations for other important reaction systems.

By utilizing my experience in catalyst characterization and design, my research plan aims to develop a framework for understanding the dynamics of multi-component catalysts in order to design novel materials for today’s energy and green chemistry challenges.

Ph.D. Advisor: Professor Maria Flytzani-Stephanopoulos

Postdoc Advisors: Professor Cynthia M. Friend and Professor Robert J. Madix