Ternary PtFeCo alloys on graphene with high electrocatalytic activities for methanol oxidation

Abstract

Ternary PtFeCo alloys as alternatives to conventional Pt electrocatalysts are highly important in the field of the methanol oxidation reaction. In this study, we demonstrate a one-pot two-step reduction method for the synthesis of graphene supported PtFeCo alloy nanocomposites as an integrated binder-free catalyst. The synergistic effect of alloying with Fe and Co as well as graphene decorating contributes to an increase in the utilization of the noble metal, namely, reducing the amount of Pt in the nanocomposites to 7%. After tailoring the elemental composition of the alloys, Pt₅₂Fe₂₉Co₁₉@G-7% exhibits a mass activity/specific activity of 1758.2 mA mg⁻¹_Pt/3.42 mA cm⁻² that is 3.13/3.45 times that of commercial Pt/C in an acidic medium. Impressively, it showed a superior mass current density of 9356.1 mA mg⁻¹_Pt at 60 °C which is close to the operating temperature of direct methanol fuel cells. Moreover, the as-obtained Pt₅₂Fe₂₉Co₁₉@G-7% also exhibited excellent CO tolerance and reliable stability compared to commercial Pt/C. The structural characterization further verifies that the surface strain and electronic effect play a critical role in determining the electrocatalytic properties of PtFeCo@G nanocomposites for the methanol oxidation reaction.