Synthesis and Evaluation of N-Doped Carbon-Based Supports and Catalysts

Synthesis and Evaluation of N-Doped Carbon-Based Supports and Catalysts

PROJECT NUMBER: 23 | AUTHOR: Denali Ibbotson, Chemical and Biological Engineering

MENTOR: Svitlana Pylypenko,  Chemistry

ABSTRACT

The widespread use of fuels such as coal, oil, and natural gas is negatively impacting the climate. To mitigate this, cleaner technologies such as fuel cells, which convert the chemical energy of the reactant into electricity, are being actively investigated. Fuel cells require the use of catalysts on both the anode and cathode sides of the fuel cell. The state-of-the-art catalyst for the oxygen reduction reaction on the cathode is platinum nanoparticles dispersed on a carbon support. It has been shown that doping of the carbon support with nitrogen functionalities improves nucleation, dispersion, performance, and stability of the catalyst. This work focuses on improving the fundamental understanding of why and how nitrogen functionalities improve the dispersion of platinum nanoparticles on carbon supports. Building on previous work, a series of nitrogen-doped carbon spheres are synthesized with controlled shape and composition to be studied as a diverse set of nitrogen-doped carbon supports. The goal of this set of materials is to explore how the presence of nitrogen in the carbon support affects the dispersion of platinum nanoparticles differently when the chemistry of the nitrogen doping, as well as the amount of nitrogen within the support, is varied. Past studies explored the effects of nitrogen on platinum dispersion when nucleated and grown in the presence of the support. In this study, platinum nanoparticles are synthesized separately from the support, to identify whether nitrogen effects similar are similar when particles are deposited directly on the support. Materials in this study are evaluated using transmission electron microscopy (STEM), paired with elemental identification using energy dispersive x-ray spectroscopy (EDS). For these studies, STEM is very useful, as it allows for the visualization of all elements along with quantification of the atomic percentages. The combination of well-designed syntheses efforts with quality characterization of these synthesized materials utilizing STEM allows for a better understanding of nitrogen effects that can be utilized to design catalysts with improved properties.

PRESENTATION

AUTHOR BIOGRAPHY

Denali Ibbotson is from Katy, TX and will be completing her B.S. in Chemical Engineering in May 2021. After graduating, she is planning on attending graduate school for Materials Science and Engineering. She joined the Pylypenko group in the Spring of 2019, and her research with the group has focused on both synthesizing and characterizing nitrogen-doped carbon supports and catalysts for fuel cells. In her free time, she enjoys spending time with her family and friends, as well as swimming, and catching up on reading.