J. Electroanal. Chem.

2017, 789,

Intermetallic compounds (IMCs) can enhance the electrocatalytic performance of the oxygen reduction reaction (ORR) because of their definite composition and structure and strong electron interaction. Here, we present a one -pot synthesis of structurally ordered Pd2Sn and Pd6Sn3Co nanoparticles supported on carbon material at low temperature without utilizing surfactant. Both XRD and high-resolution TEM results confirm the formation of IMC phase. The incorporation of Co atoms into Pd2Sn leads to a lattice contraction. EDX line scan analysis and ICP-AES demonstrate that the Pd:Sn:Co atomic ratio of ordered Pd6Sn3Co IMC is close to its nominal composition. The X-ray photoelectron spectroscopy indicates that the binding energies of Pd 3d(3/2) and Pd 3d(5/2) within the Pd6Sn3Co IMC are upshifted as compared with the Pd2Sn IMC, suggesting that a down-shift of d-band center relative to the Fermi level. This shift could explain that the Pd6Sn3Co IMC catalyst exhibits a higher activity and much better durability for the ORR in alkaline medium than the commercial Pt/C and Pd2Sn IMC catalysts. (C) 2017 Elsevier B.V. All rights reserved.