Probing Interfacial Potential under Transient Conditions via Second Harmonic Generation at Pt-water interface

The electrochemical potential of an interface can be controlled by a potentiostat, which regulates the potential difference between the working and the reference electrodes. Under transient conditions, the electrochemical potential may deviate from the applied potential due to the Ohmic resistance (the RC element in the circuit). However, characterizing this deviation has been challenging. In this thesis, an optical method based on second harmonic generation (SHG) spectroscopy is used to monitor the electrochemical potential at the platinum (Pt)–water interface during a potential sweep. The results are compared to the constant potential baseline. We observe the deviation between the electrochemical potential and the applied value and that this gap widens with the potential sweep rate. This observation is consistent with the Ohmic resistance limitation; however, even after correcting for the Ohmic drop, the gap between the electrochemical potential and the applied value persisted, especially at high scan rates. This finding suggests that there is an intrinsic reorganization of the electrical double layer (EDL) beyond the Ohmic contribution. Our finding highlights the EDL dynamics beyond the equivalent circuit model and that the interpretation of the transient potential analysis may not as straightforward as previously considered.

Name thesis:degree_name

M.S., Materials Science and Engineering

Level thesis:degree_level

Master of Science

Discipline thesis:degree_discipline

Materials Science and Engineering

Grantor

Cornell University

Year dc:date.issued

2025

Author dc:creator

• Pan, Zeyu

Committee member dc:contributor.committeemember

• Singer, Andrej

Statement dc:rights

• Attribution-NonCommercial-ShareAlike 4.0 International

Licence dc:rights.uri

• https://creativecommons.org/licenses/by-nc-sa/4.0/

Language dc:language.iso

en

DOI

https://doi.org/10.7298/vnc2-xt60

Dc Identifier Other

ProQuest Submission ID: 12607
ProQuest Publication ID: 32278564

OAI identifier oai:identifier

oai:ecommons.cornell.edu:1813/120989