Ordered Intermetallic Pd₃Bi Prepared by an Electrochemically Induced Phase Transformation for Oxygen Reduction...

Area of Science:

• Nanochemistry and Materials Science
• Electrochemical Synthesis
• Catalysis

Background:

• Ordered intermetallic nanoparticles are crucial for catalysis, superconductors, and magnetic devices.
• Synthesizing nanostructured ordered intermetallics is challenging, limiting material development.
• Existing methods face difficulties in preparing these advanced nanomaterials.

Purpose of the Study:

• To develop a facile method for synthesizing ordered intermetallic nanoparticles under ambient conditions.
• To convert existing ordered intermetallic palladium bismuth (PdBi2) into a more catalytically active phase.
• To enhance the catalytic performance of palladium-based materials for oxygen reduction reactions.

Main Methods:

• Electrochemical dealloying of colloidally synthesized ordered intermetallic PdBi2.
• Utilizing the low melting point and vacancy formation energies of PdBi2 for facile dealloying.
• Employing a vacancy diffusion mechanism for interdiffusion of constituent atoms under ambient conditions.

Main Results:

• Successfully converted ordered intermetallic PdBi2 to ordered intermetallic Pd3Bi nanoparticles.
• The resulting Pd3Bi catalyst demonstrated 11 times higher mass activity than Pt/C for oxygen reduction.
• Achieved 3.5 times higher mass activity and superior methanol tolerance compared to Pd/C.

Conclusions:

• Established a key development in synthesizing noble-metal-rich ordered intermetallic phases with high catalytic activity.
• The electrochemical dealloying process offers a viable route for creating advanced intermetallic catalysts.
• Provides guidelines for designing ordered intermetallic compounds under ambient conditions for enhanced performance.