(217d) Electrocatalysis at Buried Interfaces

Electrocatalysis underlies many emerging clean energy technologies, such as fuel cells and electrolyzers. 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 with a room temperature process and deposited as uniform and continuous layers onto thin films of Pt, 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 of silicon oxide overlayers in MCECs, we analyze their transport properties and the influence of mass transfer on the performance of thin film hydrogen evolution electrocatalysts. 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. Esposito, ACS Catalysis, vol. 8, 1767–1778, 2018.