Theses and Dissertations

ORCID

https://orcid.org/0000-0001-6028-2845

Advisor

Wipf, David O.

Committee Member

Gwaltney, Steven

Committee Member

Mlsna, Todd E.

Committee Member

Creutz, Sidney

Date of Degree

12-12-2025

Original embargo terms

Immediate Worldwide Access

Document Type

Dissertation - Open Access

Major

Chemistry

Degree Name

Doctor of Philosophy (Ph.D.)

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

This dissertation presents the fabrication and application of a 150 micrometer platinum microelectrode for induction heating, with a copper coil generating the electromagnetic field and the heating process controlled using pulse width modulation technique (PWM) to regulate the duty cycle of a high-frequency signal. Electrochemical characterization, including resonance frequency determination, peak-to-peak potential optimization, and scan rate variation, is conducted using a 5 mM [Ru(NH3)6]2+/3+ solution in 0.1 M KNO3 to calibrate current variations with changing duty cycles, while the temperature increase (delta T) is estimated using the Seebeck coefficient of [Ru(NH3)6]2+/3+. The study further explores the application of induction heating for enhancing the sluggish oxygen reduction reaction (ORR), which is vital for fuel cells and metal-air batteries. Temperature calibration is performed in 50 mM H2SO4 and 50 mM HClO4 under 20 Vpp and 30 Vpp applied induction heating potential conditions, where H2SO4 enables higher temperature rises but damages the platinum electrode, while HClO4 allows heating up to 80 degrees Celsius before electrode poisoning occurs. Electrochemical data confirm increases in the ORR diffusion coefficient and rate constant, highlighting the potential of PWM controlled heating for reaction enhancement. Additionally, the impact of electrode positioning on electrochemical parameters is examined by comparing vertically and horizontally positioned electrodes, with the latter exhibiting lower temperature increases (maximum 65 degrees Celsius) due to reduced convection. COMSOL Multiphysics simulations confirm similar heat generation and transfer for both orientations, emphasizing the role of convective differences in temperature variations. Finally, a novel temperature pulse voltammetry (TPV) technique is introduced to analyze reaction kinetics and thermodynamics, where induction heating with a 10 Vpp potential in a home-built system resulting in minimal temperature increases, and the highest current response at 975 msec suggests residual heat transfer within the electrode’s epoxy matrix.

Download

Share

COinS