Geometrically Ordered Triangular-Atom-Unit Zn-PtCo Intermetallic for Highly Efficient and Durable Fuel Cells

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Proton exchange membrane fuel cells (PEMFCs) require highly efficient and stable oxygen reduction reaction (ORR) catalysts.
• Platinum-cobalt (PtCo) intermetallics show promise but suffer from cobalt dissolution, limiting their application.

Purpose of the Study:

• To develop a stable and highly active Pt-type ORR catalyst for PEMFCs.
• To mitigate cobalt dissolution in PtCo intermetallic catalysts.

Main Methods:

• Synthesis of a partially geometrically ordered Zn-decorated PtCo intermetallic (Zn-PtCo IMC) by incorporating Zn into the PtCo lattice.
• Fabrication and testing of Zn-PtCo IMC-based fuel cells.
• Accelerated durability testing (120k cycles).
• In-depth mechanistic studies.

Main Results:

• The Zn-PtCo IMC exhibits a stable triangular-atom-unit structure, enhancing durability.
• Zn-PtCo IMC-based fuel cells achieved a power density of 1.98 W cm⁻², surpassing commercial Pt/C and disordered Zn-PtCo.
• The catalyst retained 61.2% of its mass activity after 120k cycles.

Conclusions:

• The geometrically ordered structure in Zn-PtCo IMC effectively weakens oxygen adsorption and increases cobalt diffusion energy barriers.
• This leads to significantly enhanced activity and durability compared to conventional catalysts.
• Zn-PtCo IMC represents a promising catalyst for advanced PEMFC applications.