Caltech Young Investigator Lecture

Abstract: The intermittent nature of renewable energy sources requires a clean, scalable means of converting and storing energy. Water electrolysis can sustainably achieve this goal by storing energy in the bonds of oxygen and hydrogen molecules. This seminar will present transition metal oxides as alternative oxygen catalysts to costly and scarce noble metals. Through investigation of model epitaxial oxide thin films, studies of the effect of crystallographic orientation, strain, the ligand effect, and charge transfer resistance on electrocatalysis can shed light on the reaction mechanism and what catalyst properties govern its kinetics. In addition, these well-defined surfaces allow spectroscopic examinations of their chemical speciation in an aqueous environment by using ambient pressure X-ray photoelectron spectroscopy. By quantifying the formation of hydroxyl groups, we compare the relative affinity of different surfaces for this key reaction intermediate in oxygen electrocatalysis. The strength of interaction with hydroxyls correlates inversely with activity, illustrating detrimental effects of strong water interactions at the catalyst surface. The understanding obtained from epitaxial surfaces develops molecular insight regarding interactions at oxide/water interfaces. Furthermore, fundamental understanding of the mechanisms of oxygen electrocatalysis guides the rational design of high-surface-area oxide catalysts for technical application.

Refreshments served at 3:30pm in the Spalding Laboratory Lobby.

The Young Investigators Lecture Series is sponsored by the EAS Division.