Synthesis of Au@Pt Core-Shell Nanoparticles as Efficient Electrocatalyst for Methanol Electro-Oxidation

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Bimetallic nanoparticles (NPs) with a platinum (Pt) monolayer shell are highly sought after for heterogeneous catalysis due to their superior activity and reduced Pt usage.
• Challenges persist in achieving uniform Pt monolayers and ensuring their stability on gold (Au) nanoparticle seeds.

Purpose of the Study:

• To report a controlled synthesis method for Au@Pt core-shell NPs with tunable Pt coverage.
• To investigate the electrocatalytic activity of these Au@Pt NPs for methanol electro-oxidation, focusing on the effect of Pt shell thickness.

Main Methods:

• Controlled deposition of Pt monolayer onto uniform Au NPs seeds.
• Tuning the gold-to-platinum (Au/Pt) atomic ratio by adjusting precursor solution ratios.
• Characterization using high-resolution scanning transmission electron microscopy (HR-STEM) and X-ray diffraction (XRD).
• Electrocatalytic activity assessment for methanol electro-oxidation.

Main Results:

• Successfully synthesized Au@Pt core-shell NPs with controlled Pt monolayer thickness.
• Au@Pt NPs with an atomic ratio of 1:2 (Au:Pt) demonstrated the highest electrocatalytic activity for methanol electro-oxidation.
• Both higher and lower Pt ratios resulted in diminished overall catalytic performance.
• Enhanced performance at the 1:2 ratio is attributed to weakened carbon monoxide (CO) binding on the Pt/monolayer surface.

Conclusions:

• A viable synthesis strategy for creating highly active Au@Pt core-shell NPs with minimal Pt utilization was developed.
• The study highlights the critical role of Pt shell thickness in determining catalytic efficiency.
• These findings offer a pathway for designing advanced, cost-effective electrocatalysts for fuel cell applications.