Fuel Cell Catalyst Layers with Platinum Nanoparticles Synthesized by Sputtering onto Liquid Substrates.

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Platinum nanoparticles are crucial catalysts in proton exchange membrane fuel cells.
• Traditional synthesis methods can involve contaminants and precursors.
• Sputter deposition onto liquid substrates offers a cleaner synthesis route.

Purpose of the Study:

• To present a novel method for synthesizing supported platinum nanoparticles using magnetron sputtering onto liquid poly(ethylene glycol) (PEG).
• To investigate the nanoparticle growth during a subsequent heat-treatment step.
• To evaluate the catalytic performance of the synthesized platinum nanoparticles for the oxygen reduction reaction.

Main Methods:

• Magnetron sputtering of platinum onto liquid poly(ethylene glycol) (PEG).
• Heat treatment of sputtered nanoparticles for attachment to a carbon support.
• Transmission electron microscopy (TEM) for nanoparticle characterization.
• Electrochemical measurements to assess catalytic activity for oxygen reduction reaction (ORR).

Main Results:

• Pt nanoparticle growth observed during heat treatment, facilitated by the carbon support and PEG's reducing properties.
• A bimodal size distribution of Pt nanoparticles (2.5 ± 0.8 nm and 6.7 ± 1.8 nm) was achieved after heat treatment.
• Synthesized Pt nanoparticles exhibited excellent specific activity (1.75 mA/cm² _Pt) and mass activity (0.27 A/mg_Pt) for ORR.
• Performance metrics surpassed commercial Pt/C catalysts and matched bulk Pt values.

Conclusions:

• The study demonstrates a scalable method for producing high-performance, carbon-supported Pt catalyst nanoparticles.
• Heat treatment enables controlled nanoparticle growth and attachment, enhancing catalytic efficiency.
• This approach offers a promising route for developing advanced fuel cell catalysts with efficient material utilization.