In Situ Alloying with Hybrid Mesoporous Fe-N-C to Accelerate the Catalysis Efficiency of Pt for the Oxygen Reduction Reaction

Pt-basedintermetallic alloys with high activity and stabilityare promising for accelerating the cathodic oxygen reduction reaction(ORR) and large-scale application of proton exchange membrane fuelcells. So far, facile synthesis of Pt-based alloys in less time isdesirable but still challenging. Herein, based on the traditionalwet impregnation method, facile in situ reduction of H2PtCl6 and alloying with a hybrid nanostructure mainlydoped with Fe single atoms as well as small amounts of Fe-based nanoparticlesand oxides were developed to fabricate highly dispersed PtFe nanoparticlesloaded on a mesoporous Fe-N-C support. Alloying of Ptderived from H2PtCl6 with various iron-basedspecies existing in forms of single-atom, metallic, and oxide stateswas confirmed by systematic characterization, and the Fe content inthe support is important for PtFe alloy formation, and the correspondingelectrochemical performance promotion has been identified. The as-synthesizedbest-performance PtFe/Meso-PDA-5 catalyst delivered a high potentialof 0.925 V at a current density of 3 mA cm(-2) andachieved a high mass activity of 497.5 mA mg(Pt) (-1) at 0.9 V for the ORR in 0.1 M HClO4. More importantly,only 17.9% mass activity loss was observed after 10k potential cyclesof the accelerated deterioration test. The present work provides astrategy for facile synthesis of Pt-based alloy nanomaterials forORR catalysis and highlights the importance of supports in alloy formation. PtFe nanoparticles confined in mesoporousFe-N-Cwere constructed by in situ alloying of Pt with hybrid Fe-N-Cfor sustainable fuel cells.