Grad Seminar: Prof. Daniel Esposito, Columbia University

September 29, 2020

12:00 - 1:00 PM
WebEx Webinar

Electrocatalysis at Buried Interfaces​

Prof. Daniel Esposito

Columbia University

Abstract

Electrocatalysis underlies many emerging clean energy technologies, such as fuel cells, electrolyzers, and photoelectrochemical cells. However, continued improvements in electrocatalyst activity, durability, and selectivity must be achieved in order for these technologies to make meaningful contributions to a sustainable energy future. In this presentation, I will describe unconventional electrocatalyst architectures for which metallic electrocatalysts are encapsulated by ultra-thin overlayers made of permeable oxides. These oxide layers are synthesized using a room temperature photochemical process that deposits uniform oxide overlayers onto thin films of platinum, one of the most commonly used electrocatalyst materials. Through various electroanalytical measurements, we show that these oxide overlayers can be selectively permeable to certain electroactive species and thereby enable efficient and selective electrocatalysis at the buried interface between the oxide overlayer and active catalyst. For this reason, these electrocatalysts may be referred to as membrane-coated electrocatalysts (MCECs). By systematically varying the thickness or composition of silicon oxide overlayers in MCECs, we analyze their transport properties and the influence of mass transfer on the performance of thin film electrocatalysts for the hydrogen evolution reaction. 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 at the interface. Importantly, this work highlights the potential of oxide-encapsulated electrocatalysts to serve as a tunable platform for efficient and stable electrocatalysis and/or photoelectrocatalysis of a variety of electrochemical reactions.

References

[1] N. Y. Labrador, X. Li, Y. Liu, J. T. Koberstein, R. Wang, H. Tan, T. P. Moffat, and D. V. Esposito, Nano Letters, vol. 16, 6452-6459, 2016.

[2] D.V. Esposito, ACS Catalysis, 2018, vol. 8, pp 457–465.

[3] N. Y. Labrador, E. L. Songcuan, C. De Silva, Han Chen, Sophia Kurdziel, Ranjith K. Ramachandran, Christophe Detavernier, D.V. EspositoACS Catalysis, vol. 8, 1767–1778, 2018.

Picture1.jpg

Schematic of electrocatalyst encapsulated by an ultrathin permeable overlayer that can be tuned to control reaction pathways occurring at the buried interface between the overlayer and the electrocatalyst.

Biography

Esposito joined the Chemical Engineering Department at Columbia Engineering in 2014. Prior to that, he was a postdoctoral fellow at the National Institute of Standards and Technology in the National Research Council Fellowship Program. He received his BS in chemical engineering in 2006 from Lehigh University and a PhD in chemical engineering in 2012 from the University of Delaware.

Contact Sheela Sekhar at sheela.sekhar@rutgers.edu.
Phone: (848) 445-2159