Ultra-low Pt loading membrane electrode assemblies (ULP MEAs) are prepared through in situ construction of core-shell Ir@Pt nanoparticles (ft/Vulcan XC-72R as the core) on the surface of an electrode via a pulse electrochemical deposition (PED) approach. The core material is coated on a membrane with a conventional catalyst-coated membrane process prior to the deposition of the shell metal (Pt in this case). The ULP MEAs are characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The effects of a number of preparation parameters on cell performance are investigated in detail. The performance of the ULP MEA, in which the anode loadings of Pt and metals are similar to 0.012 mg cm(-2) and 0.044 mg cm(-2)(0.012 mg cm(-2) Pt + 0.032 mg cm(-2) Ir) respectively, is found to be competitive with that of an MEA prepared with an anode Pt loading of 0.1 mg cm(-2) (commercial Pt/C catalyst from Johnson Matthey), manifesting the solid advantage of this in situ PED method. (C) 2014 Elsevier B.V. All rights reserved.