Methanol Tolerant Pt-C Core-Shell Cathode Catalyst for Direct Methanol Fuel Cells

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Methanol crossover in direct methanol fuel cells (DMFCs) leads to performance degradation and catalyst poisoning.
• Developing cathode catalysts that inhibit methanol oxidation while promoting oxygen reduction is crucial for DMFC efficiency.

Purpose of the Study:

• To synthesize and evaluate a carbon-encapsulated platinum (Pt) cathode catalyst for DMFCs.
• To investigate the effect of the carbon shell's graphitization degree on catalyst performance.

Main Methods:

• Synthesis of a Pt cathode catalyst via heat treatment of Pt-aniline complex-coated carbon nanofibers.
• Characterization of the catalyst's structure and performance in single-cell DMFC tests.

Main Results:

• The carbon shell effectively inhibited methanol crossover to the Pt core, with increased inhibition at higher graphitization degrees.
• The carbon shell permitted oxygen diffusion, allowing the Pt core to facilitate the oxygen reduction reaction (ORR).
• The synthesized catalyst demonstrated superior performance and stability compared to commercial Pt/C in single-cell tests.

Conclusions:

• Carbon-encapsulated Pt catalysts offer a promising strategy to mitigate methanol crossover in DMFCs.
• Optimizing the carbon shell's graphitization enhances its ability to suppress methanol oxidation while maintaining ORR activity.
• The developed catalyst presents a viable alternative for improving DMFC efficiency and longevity.