Undoped nanodiamond (ND) supported PtRu (PtRu/ND) electrocatalyst was prepared by a microwave heating polyol method. The alloy structures, morphology and composition of the PtRu/ND catalyst were characterized by X-ray diffraction, high-resolution transmission electron microscopy and energy-dispersive spectroscopy. The electrocatalytic activities of the PtRu/ND catalyst for methanol oxidation were also investigated by cyclic voltammetry and chronoamperometry. It was found that Ru was partly dissolved in the face-centered cubic Pt lattice. The PtRu nanoparticles were small and uniform with the size of 2-4 nm, and highly dispersed on ND supports. The electrochemical measurements demonstrated that PtRu/ND catalyst exhibited higher activity and stability for methanol electrooxidation reaction than Pt/ND catalyst. (C) 2011 Elsevier Ltd. All rights reserved.