Precisely tuning the electronic structure of ordered PtFe alloy supported on multi-walled carbon nanotubes for enhanced methanol oxidation

Abstract

The ordered intermetallic compounds have attracted significant attention due to their higher electrocatalytic activity and stability. In this study, the ordered PtFe intermetallic nanoparticles (NPs) with different feeding molar ratios of Pt and Fe supported on multi-walled carbon nanotubes (MWCNTs) have been successfully synthesized via co-engineering of the surface composition and electronic structure. Benefitting from the appropriate electronic interactions between Pt and Fe atoms, the high ordered degree of PtFe alloy and the strong interaction between PtFe intermetallic NPs and MWCNTs, the Pt1Fe2.5/MWCNTs catalyst with appropriate surface composition displays better activity, stability, and anti-CO poisoning capability in methanol oxidation as compared to the commercial Pt/C catalyst. Specifically, the mass and specific activity of the Pt1Fe2.5/MWCNTs catalyst is 1.01 mA.ug−1Pt and 1.85 mA.cm−2, which are enhanced by 5.31 and 6.85 times relative to the values of commercial Pt/C catalyst, respectively. Moreover, the CO oxidation on the surface of the Pt1Fe2.5/MWCNTs catalyst (0.703 V) starts earlier than on the commercial Pt/C catalyst (0.801 V). The demonstrated strategy provides new insight into the preparation of Pt-based catalysts with controllable surface composition and high catalytic performance.