Author ORCID Identifier

Date Available


Year of Publication


Degree Name

Master of Science (MS)

Document Type

Master's Thesis


Arts and Sciences



First Advisor

Doo Young Kim


Fuel cells are considered a promising technology for achieving cleaner and more sustainable energy production and utilization. However, one of the current major challenges is the economic viability associated with the extensive use of Pt group metal (PGM) catalysts, particularly on the cathode side. Therefore, non-PGM single-atom catalysts (SACs) have received considerable attention as alternatives for PGM catalysts in the oxygen reduction reaction (ORR), which occurs at the cathode of the fuel cell. Among various SAC structures, the non-PGM/nitrogen-doped carbon-based structure (M-N-C) stands out for its excellent ORR performance.

Chapter 2 illustrates the use of copper metal in place of PGM. Cu-N-C was synthesized via a simple pyrolysis method using pyrene-derived graphene quantum dots as a carbon precursor in the presence of urea as the nitrogen source. Abundant nitrogen atoms in pyrolyzed carbon network derived from graphene quantum dots enable the chelation of metal atoms, which facilitates the inclusion of a higher loading of Cu atoms. This is a significant advancement in the field of work. Cu-N-C was prepared using 24.7% copper loading, demonstrating the most promising ORR activity. Additionally, an acid-washing step was introduced to enhance the ORR catalytic activity by removing copper nanoparticles, reducing electrolyte pollution, and improving catalyst stability. This study revealed that the L2 Cu-N-C after acid washing exhibited superior performance over the before-acid-washed catalyst sample.

In Chapter 4, CO stripping voltammetry of Pt-SACs was performed to evaluate the number of active sites contributing to an electrochemical reaction.CO oxidation potential depends on particle size. This work suggests that CO stripping can be employed not only for determining the active sites based on site density (SD)but also reveals the particle size distribution.

Digital Object Identifier (DOI)

Funding Information

The University of Kentucky (material research RPA) and the National Science Foundation (award number 2327349).

Available for download on Friday, November 08, 2024