Tailoring COFs with Water and Oxygen Pathways for Efficient Catalyst Interfaces in PEMFCs.

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Proton exchange membrane fuel cells (PEMFCs) offer high efficiency and clean emissions.
• Reducing platinum (Pt) catalyst loading in PEMFCs is hindered by mass transport resistance.
• Optimizing the three-phase interface is crucial for improved PEMFC performance.

Purpose of the Study:

• Investigate phosphorylated covalent organic frameworks (P-rCOFs) as ionomers for PEMFCs.
• Enhance water and oxygen mass transfer at the catalyst surface.
• Improve the catalytic performance and reduce Pt loading in PEMFCs.

Main Methods:

• Synthesized P-rCOFs with engineered side chains and protonated tertiary amine sites.
• Incorporated P-rCOFs as ionomer binders in PEMFC electrodes.
• Evaluated electrochemical performance using techniques like cyclic voltammetry and polarization curves.

Main Results:

• P-rCOF-C4 demonstrated a 37 mV higher half-wave potential compared to Nafion.
• PEMFCs with P-rCOF-C4 achieved a peak power density of 2.40 W cm^-2.
• A 1.5-fold increase in peak power density was observed with P-rCOF-C4 at low Pt loading.

Conclusions:

• P-rCOFs effectively optimize the three-phase interface in PEMFCs.
• This approach enhances mass transfer and catalytic activity.
• P-rCOFs present a promising strategy for developing efficient and cost-effective PEMFCs.