Zinc Intercalated Lattice Expansion of Ultrafine Platinum–Nickel Oxygen Reduction Catalyst for PEMFC

Abstract Platinum (Pt)‐based membrane electrode assembly (MEA) catalysts with high performance under operating proton exchange membrane fuel cells (PEMFCs) conditions are a prerequisite for practical applications. As indicated by theoretical calculations, lattice expansion in zinc (Zn)‐intercalated Pt alloys can weaken the adsorption of oxygen intermediates, enabling strong electronic interaction for boosting MEA catalysis. To test this hypothesis, herein, a new class of carbon (C)‐supported ultrafine Pt alloys with the assistance of Zn is explored. Detailed characterizations indicate that the introduction of Zn can reduce the particle size, and simultaneously intercalates into the Pt alloys, resulting in the lattice expansion for enhancing metallic state of Pt and lowering d‐band center. This intercalation strategy can be extended to PtNi, PtCo, as well as Pt. As a result, the optimized Zn‐PtNi/C exhibits superior MEA activity (937.6 mW cm⁻² of peak power density), much higher than those of corresponding PtNi/C (771.6 mW cm⁻²) and commercial Pt/C (700.7 mW cm⁻²) under the harsh operating fuel cell conditions. This work opens up a new avenue for creating high‐performance PEMFC catalysts in terms of lattice engineering.