Daniel Esposito, Associate Professor, Department of Chemical Engineering, Columbia University
"Controlling Electrocatalytic Reactions at Buried Interfaces for Solar Fuels Applications"
Electrocatalysis underlies many emerging clean energy technologies, such as fuel cells, electrolyzers, photocatalytic reactors, and photoelectrochemical cells. However, continued improvements in electrocatalyst activity, durability, and selectivity must be achieved for these technologies to make meaningful contributions to a sustainable energy future. In this seminar, I will describe electrocatalysts for which the active electrocatalyst material is encapsulated by ultra-thin overlayers consisting of semi-permeable oxide materials. These oxide layers are synthesized using a low temperature wet chemical process and deposited as uniform overlayers onto model thin film electrodes. Electroanalytical measurements show that these oxide overlayers can be selectively permeable to certain electroactive species and thereby leverage transport phenomena to enable efficient and selective electrocatalysis or photocatalysis at the buried interface between the oxide overlayer and active catalyst. I will present several examples that show how the thickness and composition of nanoscopic oxide overlayers influence their transport properties and the performance of encapsulated electrodes. This talk will also describe characterization of the electroactive buried interface and discuss challenges and opportunities for controlling reaction pathways through modification of the physical, chemical, and/or structural properties of oxide overlayers. Importantly, this work highlights the potential of the oxide-encapsulated electrocatalyst architecture to enable efficient, selective, and stable (photo)electrocatalytic energy conversion for a wide range of electrochemical reactions and applications.
Daniel Esposito received his Ph.D. in Chemical Engineering from the University of Delaware and studied as a postdoctoral research associate at the National Institute of Standards and Technology (NIST) under a National Research Council fellowship. He is now an Associate Professor in Chemical Engineering at Columbia University, where he is also a core member of the Columbia Electrochemical Energy Center (CEEC) and Lenfest Center for Sustainable Energy. His group’s research interests relate broadly to the development of electrochemical technologies for sustainable production of chemicals and fuels. Specific topics of interest include electrocatalysis, photoelectrochemistry/solar fuels, membraneless electrochemical cells, and the use of in situ analytical techniques to study the performance and properties of (photo)electrocatalytic materials at high spatial resolution. Esposito was named a Scialog Fellow in Advanced Energy Storage and received an NSF CAREER to study electrochemical reactions at buried interfaces. He is also a co-founder and advisor of the start-up company, sHYp BV PBC, which is based on technology developed by the Esposito Lab.