Addressing the instability issue of Fe-N4-C single atom catalysts for oxygen reduction reaction (RPA Pilot / Seed Project)

Oxygen reduction reaction (ORR) is a key cathodic reaction that determine the overall performance of electrochemical conversion and energy storage devices. Platinum (Pt) nanoparticles attached to high-surface-area carbon support (Pt/C) are a state-of-the-art catalyst for ORR. However, Pt/C is not suitable for commercial application because of the expensiveness and scarcity of Pt. Therefore, it is pivotal to develop alternative catalysts that require no or sufficiently less Pt. Fe-N4-C single atom catalysts (SACs), where atomically dispersed iron (Fe) is coordinated with 4 nitrogen atoms and embedded in porous, conductive graphitized carbon network, have shown excellent ORR activity. Despite its potential, there is a significant knowledge gap in structure-property-function relationship. More importantly, a gradual decay in the long-term ORR activity of Fe-N4-C is a critical hurdle to overcome for the large-scale implementation of this catalyst into electrochemical devices. To tackle the critical challenges, this project will (1) determine chemical nature and local environment of Fe-N4-C active sites using CO stripping voltammetry and IR spectroscopy, (2) determine deactivation mechanism of Fe-N4-C upon prolonged electrochemical operation, and (3) investigate ORR mechanistic pathway of Fe-N4-C.