Electrocatalytic Performance of S-Doped FeN4@MWCNTs Nanocomposites

Author

• Ronit Lavjibhai Chaudhari, Pittsburg State UniversityFollow

Date of Award

Winter 12-13-2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Materials Science

First Advisor

Dr. Ram K. Gupta

Second Advisor

Dr. Serif Uran

Third Advisor

Dr. Timothy Dawsey

Keywords

HER, OER, ORR, MOR, LSV, Electrocatalyst

Abstract

The thesis titled “Electrocatalytic Performance of S-Doped FeN₄@MWCNTs Nanocomposites” explores the development of sulfur-doped iron-nitrogen-carbon nanotube (S-dopedFeN₄@MWCNTs) nanocomposites as high-performance an electrocatalyst for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). These reactions are crucial for technologies like fuel cells, metal-air batteries, and water-splitting systems, which are vital for renewable energy and hydrogen production.

The research demonstrates that S-doped FeN₄@MWCNTs show significantly enhanced catalytic activity compared to traditional platinum-based catalysts and undoped FeN₄@MWCNTs. Sulfur doping results in a lower overpotential for both OER and HER. For example, the S-doped FeN₄@MWCNTs catalyst exhibited an overpotential of 274 mV for OER at a current density of 10 mA/cm², compared to 283 mV for undoped FeN₄@MWCNTs and 305 mV for Iridium Oxide, a common benchmark catalyst. Similarly, for HER, the overpotential was reduced to 137 mV for S-doped FeN₄@MWCNTs, compared to 177 mV for undoped FeN₄@MWCNTs, demonstrating superior catalytic efficiency.

The catalyst also showed excellent stability, maintaining a current density of 120 mA/cm² over 20 hours during chronoamperometric testing, with only a slight decrease to 118 mA/cm². This indicates that sulfur doping enhances both the activity and durability of the catalyst. Furthermore, Tafel slopes-key indicators of reaction kinetics-were found to be 39 mV/dec for OER and 150 mV/dec for HER in the S-doped FeN₄@MWCNTs, compared to 53 mV/dec and 144 mV/dec for undoped FeN₄@MWCNTs, respectively.

The combination of iron, nitrogen, and sulfur within the carbon nanotube framework enhances the catalyst's electronic properties and increases the density of active sites. This results in faster electron transfer and improved reaction kinetics for ORR, OER, and HER. The findings suggest that S-doped FeN₄@MWCNTs can serve as a low-cost, high-performance alternative to precious metal-based catalysts, with significant implications for the advancement of sustainable energy technologies.

Recommended Citation

Chaudhari, Ronit Lavjibhai, "Electrocatalytic Performance of S-Doped FeN4@MWCNTs Nanocomposites" (2024). Electronic Theses & Dissertations. 824.
https://digitalcommons.pittstate.edu/etd/824