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Recent experimental studies have shown that the FePt nanoparticles (NPs) assembled on graphene exhibit enhanced durability and catalytic activity for oxygen reduction reaction (ORR) than Pt-only catalysts. In this work, we have performed density functional theory calculations to investigate the stability and reactivity of several FePt NPs deposited on defective graphene for ORR, where n is adopted as 0, 1, 2, and 3, respectively. The results indicate that the alloying between Fe and Pt can enhance the stability of NPs and promote their oxygen reduction activity. Moreover, the monovacancy site in the graphene can provide anchoring sites for these bimetallic NPs by forming strong metal-substrate interaction, ensuring their high stability. Importantly, the O adsorption on these composites is weakened in various ways, which is ascribed to the change in their averaged d-band center. Thus, these composites exhibit superior catalytic performance in ORR by providing a balance in the O binding strength that allows for enhanced turnover. Our results may be useful to unravel the high stability and reactivity of defective graphene-FePt NPs for ORR from a theoretical perspective. [ABSTRACT FROM AUTHOR]

Recent studies have suggested that graphene can serve as an excellent support material for the synthesis of advanced metal nanoparticle-graphene electrocatalysts. Compared with single-metal systems, rational design of bimetallic nanostructures with various compositions can provide more attractive opportunities to enhance their functionalities because of the novel electronic and magnetic properties. In this study, we have studied the adsorption of a series of bimetallic FePt clusters ( n + m ≤ 4) on defective graphene with monovacancy by performing density functional theory calculations. Particular attention is paid to addressing the structural stability and exploring the effects of FePt clusters anchoring on the electronic and magnetic properties of defective graphene. The results reveal that all studied FePt clusters can be stably adsorbed on defective graphene, with large binding energies ranging from 6.44 (for FePt) to 7.94 eV (for FePt). Moreover, the functionalized defective graphenes exhibit semiconducting or half-metallic nature, which is dependent on the values of n and m. Meanwhile, most of decorated defective graphenes exhibit nonzero magnetic moments, contributed mainly by the adsorbed clusters. In addition, these composites of FePt/graphenes possess high chemical reactivity toward O. The elongation of the O-O bonds of the adsorbed O molecules indicates that they can be used as oxidative catalysts. [ABSTRACT FROM AUTHOR]