Facile Preparation of Pt ₃ Co@Pt Core@Shell Nanoparticles as Cathode Catalysts for Fuel Cell Applications

Proton exchange membrane fuel cells (PEMFCs) offer an efficient way to generate electricity from sustainable fuels. However, the preparation of catalysts with reduced Pt and improved activity for the oxygen reduction reaction (ORR) continues to be a challenge. In this study, Pt3Co@Pt core@shell nanoparticles supported on hybrid carbon materials are prepared through a one-pot, two-step procedure: Pt and Co are first coreduced to form the Pt3Co core, followed by the overgrowth of a Pt shell. This approach provides simplified synthesis with fewer steps, low-cost equipment, mild conditions, high yield, and potential for large-scale production. The Pt3Co@Pt nanoparticles have an average size of 3.99 nm, with an average Pt shell thickness of 0.71 nm. The Pt3Co@Pt/C catalyst exhibits a 2.31-fold higher electrochemical surface area (ECSA, 109 m2/g) and a 1.86-fold higher mass activity (MA, 446 mA/mgpt) compared to the commercial Pt/C in half-cell testing. Single-cell test results indicate that the membrane electrode assembly (MEA) made with Pt3Co@Pt/C achieves a peak power density of 0.80 W/cm2 at a backpressure of 100 kPag, compared to 0.71 W/cm2 for the MEA using commercial Pt/C. This activity enhancement is attributed to the optimized particle size and synergetic effect between Pt and Co within the core@shell configuration. The Pt shell serves as a protective layer, leading to less than 15% loss of ECSA and MA after the durability test, compared with over 20% loss for commercial Pt/C. Such results demonstrate the feasibility of improving ORR performance by constructing core@shell catalysts through a simple, scalable method, supporting their practical applications in PEMFCs.