Surfactant-free synthesis of highly methanol-tolerant, polyhedral Pd-Pt nanocrystallines for oxygen reduction reaction

Carbon supported polyhedral Pd–Pt nanocrystallines (Pd–Pt/C) are synthesized using a facile surfactant-free process. The morphology of nanocrystallines is tailored by ammonia complexation and Pd/Pt ratios of the metallic precursors. The as-prepared Pd–Pt/C catalysts with low Pt content exhibit oxygen reduction reaction (ORR) activity comparable to that of the commercial Pt/C catalyst, while having much higher methanol tolerance. Compared with the spherical Pd6Pt/C catalyst, the polyhedral Pd6Pt/C catalyst shows 1.56-fold higher mass specific activity for ORR, while its electrochemical surface area (ECSA) is only half of the former. The superior ORR activity may be attributed to the more exposed regular (111) planes, the higher ratio of metallic form and the surface enrichment of Pt atoms.