Two-Step Dry Synthesis of Binderless 3D Low Pt-Loading Electrocatalysts for Direct Alkaline Methanol Fuel Cell Anodes

Three-dimensional (3D) porous electrocatalysts of low platinum loading were synthesized by gas-phase pulsed laser ablation (PLA) and deposited on multiwalled carbon nanotubes (MWCNTs) directly grown on a stainless steel mesh current collector by catalyst-free chemical vapor deposition (Pt/MWCNT/SS). The performance of the developed electrocatalysts was evaluated for the methanol oxidation reaction (MOR). The PLA chamber pressure and ablation time were optimized to achieve the highest methanol oxidation current per Pt loading and electrochemically active surface area while maintaining structural stability. The most robust electrocatalyst, obtained with PLA at 10(-5) Torr for 5 min, exhibited a 50% higher methanol oxidation current compared to the commercial Pt/C with similar Pt loading. In addition, it showed the lowest loss of active sites after stability tests while maintaining its structural integrity. Increasing the electrolyte temperature from 0 to 80 degrees C significantly improved the methanol oxidation current on Pt/MWCNT/SS by 13 times compared to 5.8 times for Pt/C. Electrochemical impedance spectroscopy confirmed the faster kinetics of MOR and accelerated oxidation of adsorbed CO on the surface of the Pt/MWCNT/SS relative to the Pt/C.

Automated summary

3D porous electrocatalysts with low platinum loading were synthesized using gas-phase pulsed laser ablation, showing higher methanol oxidation current and lower loss of active sites compared to commercial Pt/C. Increasing the electrolyte temperature significantly improved the efficiency of the electrocatalysts.