Embedding Pt Nanocrystals in N-Doped Porous Carbon/Carbon Nanotubes toward Highly Stable Electrocatalysts for the Oxygen Reduction Reaction

The development of highly stable and efficient catalysts for sluggish cathode oxygen reduction reaction (ORR) is extremely important for the long-term operation and the commercialization of proton exchange membrane fuel cells (PEMFCs) but still challenging. We present herein a facile strategy to efficiently embed Pt nanocrystals into N-doped porous carbon/carbon nanotubes (Pt@CNx/CNT). The N-doped porous carbon shells not only effectively prevented Pt nanocrystals from detachment, dissolution, migration, and aggregation during accelerated durability tests or heat-treatment at 900 °C, but also allowed the access of electrolyte to the Pt surface and preserved the good electron transfer of CNT by avoiding the structural damage of carbon nanotubes (CNTs). The interaction between the embedded Pt nanocrystals and the encapsulating CNx layer was found in Pt@CNx/CNT, which markedly affected the electronic structure of Pt nanocrystals and contributed to the improvement on the catalytic activity and stability of Pt@CNx/CNT. As a result, the Pt@CNx/CNT catalyst exhibited an excellent thermal stability, durability, and sufficient catalytic activity for ORR. The demonstrated strategy could be easily extended to produce a wide range of other electrocatalysts with even better activity and extraordinary stability.