1. events
  2. all
  3. 2024
  4. cpos seminar probing electrochemical noise during faradaic processes

CPOS Seminar: Probing Electrochemical Noise during Faradaic Processes

Date and Time
Location
Hybrid: CPOS Conference Room - PSBN 2520D / Zoom
Kaden Wheeler, PhD Student
Kaden Wheeler, PhD Student

Speaker: Kaden Wheeler, PhD Student, Department of Chemistry, UC Santa Barbara, Sepunaru Group

Abstract: Single-entity electrochemistry is a promising technique that probes the electrochemical response of individual particles. As electrode sizes approach the scale of micrometers or smaller, nanoparticle impacts and individual nanoparticle catalysis becomes detectable. However, as these systems approach smaller scales, noise becomes more prevalent. In this presentation, I will discuss how we understand the dominant source of noise in an electrochemical measurement, and the total magnitude of this noise. The noise in the measurement was probed by varying electrode size, sampling frequency, and redox-probe concentration during electrochemical techniques such as: chronoamperometry and electrochemical impedance spectroscopy (EIS). 

Previous results claim that electrochemical noise scales with the square root of current. However, our chronoamperometric measurements reveal that the background noise level scales linearly at the microscale. Moreover, a chemically-coupled reaction that regenerates the initial redox species yields lower noise in comparison with a purely electrochemical reaction that produces the same steady-state current. In combination, these results suggest that both the concentration of redox-active species and their diffusion contributes to the magnitude of noise. Similarly, preliminary EIS results  show that either a diffusional resistance or a Warburg-like element may be the dominant source of noise in our electrochemical cell. By understanding these noise sources, we may begin to control them, extending the detection limit of single-entity measurements.