High-density small Pt3Fe@Pt nanoparticles in carbon materials becoming superior bi-functional catalysts by oxygen-bridged with Fe single atoms

Abstract

In this work, we reported the synthesis of high-density small Pt₃Fe@Pt nanoparticles with atomic Pt shells (HDS Pt₃Fe@Pt NPs) bonded with more Fe single atoms (Fe SAs) via O-bridges loaded in the carbon materials (HDS Pt₃Fe@Pt-O-Fe-SA NP/C catalysts). The reduction in the overall size and the thickness of Pt shells (up to 1 ~ 2 atomic layers) of Pt₃Fe@Pt NPs can contribute to further reduce the d-band center of Pt, and then enhance the desorption ability of oxygen-containing intermediates in the alkaline ORR and *H in the acidic HER. Moreover, the formation of more O-bridges between Pt₃Fe@Pt NPs and Fe SAs can result in stronger electronic interactions between them. Accordingly, the as-prepared HDS Pt₃Fe@Pt-O-Fe-SA NP/C catalysts can show the superior electrocatalytic performance towards both the alkaline ORR and the acidic HER combined with other merits. For instance, the half wave potential (E_1/2) and the overpotential at a current density of 10 mA cm^-2 (η₁₀) of the as-prepared HDS Pt₃Fe@Pt-O-Fe-SA NP/C catalysts towards the alkaline ORR and the acidic HER are 0.965 V and 1 mV, respectively, which are 98 mV higher and 26 mV lower than those (0.867 V and 27 mV) of commercial Pt/C catalysts.