In this work, we have prepared porous PtPd alloyed nanoflowers uniformly supported on reduced graphene oxide by a simple and facile wet-chemical method, with the assistance of cytosine as a structure-directing agent. The products were mainly characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The as-prepared nanocomposites displayed improved electrocatalytic performances toward ethanol oxidation in alkaline media and oxygen reduction in acidic media, which make it a promising electrocatalyst in fuel cells. (C) 2015 Elsevier Ltd. All rights reserved.