High-Strength Polyurethane Composite Film Reinforced by Cellulose Nanocrystals

Development of highly active and durable catalysts for oxygen reduction reaction (ORR) alternative to Pt-based catalyst is an essential topic of interest in the research community but a challenging task. Here, we have developed a new type of face-centered tetragonal (fct) PdFe-alloy nanoparticle-encapsulated Pd (fct-PdFe@Pd) anchored onto nitrogen-doped graphene (NG). This core–shell fct-PdFe@Pd@NG hybrid is fabricated by a facile and cost-effective technique. The effect of temperature on the transformation of face-centered cubic (fcc) to fct structure and their effect on ORR activity are systematically investigated. The core–shell fct-PdFe@Pd@NG hybrid exerts high synergistic interaction between fct-PdFe@Pd NPs and NG shell, beneficial to enhance the catalytic ORR activity and excellent durability. Impressively, core–shell fct-PdFe@Pd@NG hybrid exhibits an excellent catalytic activity for ORR with an onset potential of ∼0.97 V and a half-wave potential of ∼0.83 V versus relative hydrogen electrode, ultrahigh current density, and decent durability after 10 000 potential cycles, which is significantly higher than that of marketable Pt/C catalyst. Furthermore, the core–shell fct-PdFe@Pd@NG hybrid also shows excellent tolerance to methanol, unlike the commercial Pt/C catalyst. Thus, these findings open a new protocol for fabricating another core–shell hybrid by facile and cost-effective techniques, emphasizing great prospect in next-generation energy conversion and storage applications.