Interfacial S-functionalized high-performance L1₂Pt₃Fe/Fe-SNC for proton exchange membrane fuel cells

Alloying platinum with other 3d transition metals (M) in an organized manner is a proven method to enhance the activity and lifespan of Pt catalysts utilized in proton exchange membrane fuel cells (PEMFC). Herein, a distinct composite has been engineered, featuring structured Pt–Fe intermetallic compounds (L1₂Pt₃Fe NPs) supported on an iron-doped sulfur-nitrogen-carbon (Fe-SNC) support. The L1₂Pt₃FeNPs function as the primary catalytic core for the oxygen reduction reaction (ORR) instead of the conventional Pt NPs. The sulfur atom on the Fe-SNC can secure L1₂Pt₃Fe NPs to prevent their aggregation during elevated temperature and operational phases. Additionally, the presence of S atoms can regulate the electronic configuration of platinum and decrease the bond strength between Pt and oxygen-containing intermediates. Consequently, the L1₂Pt₃Fe/Fe-SNC catalyst demonstrates exceptional catalytic efficiency and longevity for ORR with E_1/2 of 0.911 V as well as a mass activity (MA) of 0.47 A/mg_Pt. The L1₂Pt₃Fe/Fe-SNC maintains outstanding ORR stability (MA form 0.47 A/mg_Pt to 0.38 A/mg_Pt) after 30,000 cycles of AST. Impressively, the L1₂Pt₃Fe/Fe-SNC has a power density of 1.547 W/cm²·H₂–O₂ and 0.669 W/cm²·H₂-Air at 0.4 V (cathode Pt loading: 0.04mg_Pt/cm²) better than commercial Pt/C in PEMFC single-cell. This work provides new ideas for constructing various PtM intermetallic catalysts.