Semimetal-triggered covalent interaction in Pt-based intermetallics for fuel-cell electrocatalysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Platinum-based intermetallic compounds (IMCs) are crucial electrocatalysts for energy technologies like fuel cells.
• Conventional IMC synthesis requires high temperatures, often negatively impacting catalyst structure and performance.
• A need exists for advanced electrocatalysts with improved synthesis methods and superior activity.

Purpose of the Study:

• To investigate the use of semimetal atoms to lower synthesis temperatures for platinum-based IMCs.
• To explore the impact of semimetal-induced covalent interactions on catalyst properties.
• To enhance electrocatalytic performance, particularly CO tolerance, in fuel cell applications.

Main Methods:

• Synthesis of platinum-semimetal intermetallic compounds (Pt-Ge, Pt-Sb, Pt-Te).
• Characterization of structural and electronic properties influenced by d-p π backbonding.
• Electrochemical testing for oxygen reduction reaction (ORR) activity and CO poisoning resistance.

Main Results:

• Semimetal-Pt IMCs synthesized at significantly lower temperatures (300 K reduction).
• Demonstrated strong covalent interactions (d-p π backbonding) promoting ordered Pt-M bonds.
• Achieved superior CO-tolerant oxygen reduction activity (0.794 A mg⁻¹ at 0.9 V) with minimal decay (5.1%) under CO poisoning.

Conclusions:

• Semimetal incorporation offers a novel strategy to overcome temperature limitations in IMC synthesis.
• The covalent interactions in semimetal-Pt IMCs enhance electron transport and active site orbital filling.
• Semimetal-Pt IMCs represent a promising class of advanced electrocatalysts for fuel cells.