Simultaneously Geometrical and Electronic Modulation of L₁₀-PtZn by Trace Ge Boosts High-performance Oxygen Reduction...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Proton exchange membrane fuel cells (PEMFCs) require efficient electrocatalysts for widespread adoption.
• Developing low-platinum catalysts for the oxygen reduction reaction (ORR) is crucial for reducing costs and improving performance.

Purpose of the Study:

• To develop a highly active, durable, and low-platinum electrocatalyst for the ORR.
• To investigate the role of trace germanium (Ge) in enhancing the properties of PtZn intermetallic nanoparticles.

Main Methods:

• Synthesis of ultrafine PtZn intermetallic nanoparticles confined in nitrogen-doped porous carbon (Ge-L10-PtZn@N-C).
• Electrochemical characterization of the catalyst's ORR activity and performance in PEMFCs.
• Density Functional Theory (DFT) calculations to elucidate the mechanism of Ge's influence.

Main Results:

• Ge-L10-PtZn@N-C exhibited superior ORR mass activity (3.04 A mg-1 Pt) and specific activity (4.69 mA cm-2), significantly outperforming commercial Pt/C.
• PEMFCs assembled with the catalyst showed high peak power densities in both alkaline (316.5 mW cm-2) and acidic (417.2 mW cm-2) media.
• DFT calculations confirmed Ge's role in inhibiting nanoparticle growth, enhancing dispersion, and optimizing electronic structure for ORR.

Conclusions:

• Trace germanium incorporation effectively enhances the activity and stability of low-platinum PtZn electrocatalysts.
• The developed Ge-L10-PtZn@N-C catalyst represents a promising advancement for cost-effective and high-performance PEMFCs.