Synergistic multiple effects by de-alloyed strategy for efficient and durable oxygen reduction

Pt-based nanocrystals are promising candidates as oxygen reduction reaction (ORR) catalysts in fuel cells, however, their insufficient electrocatalytic activity and inferior stability create a great barrier to commercialization. Thus, it is urgent to develop high-performance Pt-based catalysts. Herein, the PtCu@Pt/C core-shell octahedral nanocrystals with the (111) plane on the surface are successfully fabricated through a liquid phase method without using surfactant and acid-etching. Benefiting from the synergistic effects of ligand, facet, and strain effects, the nanocrystals exhibit a mass activity of 2.35 A mg−1Pt and a specific activity of 6.45 mA cm−2 at 0.9 V, which are higher than those of commercial Pt/C catalysts. More significantly, the mass activity of the PtCu@Pt/C nanocrystals only lessened by 8.5 % after undergoing 10,000 cycles of accelerated durability test. This work highlights the critical role of multiple effects in determining the enhanced ORR performance of PtCu catalysts and provides a promising strategy for the rational preparation of Pt-based ORR catalysts with optimal performance. [Display omitted] •Uniform PtCu/C octahedral nanocrystals were synthesized without using surfactant.•Acid-etching can avoid the influence of Cu2+ on the ORR electrocatalysis system.•De-alloyed strategy inducing multiple effects enhanced its ORR performance.