High-Yield Synthesis of FeNC as Support of PtFe Nanoparticles for the Oxygen Reduction Reaction by a Green Ball Milling Method.

Abstract

Enhancing catalytic activity, durability and reducing costs are major challenges in commercialization of proton exchange membrane fuel cells (PEMFCs). Non-precious metal catalysts face durability challenges when applied to PEMFCs, while platinum (Pt)-based catalysts are hampered by their high costs and weak interactions with carbon supports, limiting their application in PEMFCs. Combining Pt-based catalysts with iron-nitrogen-carbon (FeNC) supports can improve the oxygen reduction reaction (ORR) performance. However, traditional preparation methods for FeNC supports, such as liquid-phase and hydrothermal synthesis, are cumbersome and have low yield. Here, we introduce a simple ball-milling method to synthesize FeNC with high yield that achieves a high-surface-area and uniform dispersion of Fe atoms. The FeNC support anchors PtFe nanoparticles at FeNₓ sites. This enhances support-alloy interactions and suppresses particle aggregation. The obtained catalyst denoted as PtFe/B-FeNC exhibits an exceptional mass activity of 2.57 A mgPt-1 at 0.9 V, representing a 12.2-fold increase compared to the commercial Pt/C. There is only 30 mV degradation for the catalyst after 120k cycles, indicating outstanding stability. This research paves the way for the green synthesis of PtFe/B-FeNC with high yield, facilitating the development of commercial materials for other electrochemical devices.