Developing highly efficient non-Pt catalysts for fuel cells and metal-air batteries is highly desirable but still challenging due to the sluggish oxygen reduction reaction (ORR). Herein, a facile and efficient strategy is demonstrated to prepare N-doped carbon encapsulated ordered Pd-Fe intermetallic (O-Pd-Fe@NC/C) nanoparticles via a one-step thermal annealing method. The obtained O-Pd-Fe@NC/C nanoparticles show enhanced ORR activity, durability and anti-poisoning capacity in both acid and alkaline medium. When O-Pd-Fe@NC/C serving as cathode catalyst for Zn-air battery, it exhibits higher voltage platform and superior cycling performance with respect to the Zn-air battery based on the mixture of Pt/C and Ir/C catalysts. The enhanced electrocatalytic performance can be ascribed to the formation of face-centered tetragonal (fct) Pd-Fe nanoparticles, the protective action of the N-doped carbon layer and the interface confinement effect between them. The in situ formed N-doped carbon shell not only restrains the Pd-Fe ordered intermetallics from aggregating effectively during the thermal annealing process, but also provides a strong anchoring effect to avoid the detachment of Pd-Fe nanoparticles from the carbon support during the potential cycling. This facile carbon encapsulation strategy may also be extended to the preparation of a wide variety of N-doped carbon encapsulated intermetallic compounds for fuel cell application.

迫切需要开发用于燃料电池和金属空气电池的高效非Pt催化剂，但是由于缓慢的氧还原反应（ORR）而仍然具有挑战性。在本文中，证明了一种简便有效的策略，可通过一步热退火方法制备N掺杂碳包封的有序Pd-Fe金属间化合物（O-Pd-Fe @ NC / C）纳米粒子。所得的O-Pd-Fe @ NC / C纳米粒子在酸性和碱性介质中均显示出增强的ORR活性，耐久性和抗毒能力。当O-Pd-Fe @ NC / C用作锌空气电池的阴极催化剂时，相对于基于Pt / C和Ir / C催化剂混合物的锌空气电池，它表现出更高的电压平台和优异的循环性能。 。增强的电催化性能可归因于面心四方（fct）Pd-Fe纳米颗粒的形成，N掺杂碳层的保护作用以及它们之间的界面限制作用。的原位形成的N掺杂碳壳不仅在热退火过程中有效地抑制了Pd-Fe有序金属间化合物的有效聚集，而且还提供了强大的锚固效果，避免了Pd-Fe纳米粒子在电势循环过程中从碳载体上脱离。 。这种简便的碳包封策略也可以扩展到制备用于燃料电池应用的各种N掺杂的碳包封的金属间化合物。