September 24
@
4:00 PM
–
5:00 PM
Zahra Fakhraai
Department of Chemistry
University of Pennsylvania Philadelphia
Philadelphia, PA
Interface Evolution During Electrochemistry
Photoelectrochemical reactions have emerged as a direct pathway to harvest solar energy for sustainable chemistry. However, understanding and controlling the complex microenvironments of solid electrodes or hybrid interfaces of two-dimensional materials is critical for ensuring their long-term functionality while optimizing a desired reaction. In this talk, I will discuss how in-situ spectroscopic ellipsometry can be utilized to probe the dielectric environment of hybrid interfaces during electrochemical processes. Using this technique, we can visualize the kinetics of the electric double layer, probe the stability of anchored molecular catalysts on silicon substrates, and understand the role of oxide rearrangements in apparent variations during the first few electrochemical cycles.
I will also demonstrate that on metallic electrodes, slow interfacial water can significantly slow down the motion of ions in the electrical double layer, with kinetics that are much slower than the response time of an electrochemical cell. This slow rearrangement kinetics can potentially explain previously unknown phenomena such as the apparent formation of hydrogen bubbles on metallic nanoparticles.