A simple and rapid one-pot wet-chemical method is developed for large-scale preparation of reduced graphene oxide nanosheets supporting Pt-Pd nanoflowers (Pt-Pd NFs/RGOs) using hydrazine hydrate as a reducing agent, without any seed, template, organic solvent, or special apparatus. The coexistence of sodium nitrite (NaNO2) and poly(vinyl pyrrolidone) (PVP), and their amounts are essential for synthesis of flower-like nanostructures. Besides, Pt-Pd NFs/RGOs have higher catalytic activity and better durability for oxygen reduction reaction, compared with commercial Pt-C (50 wt %). (C) 2014 Elsevier B.V. All rights reserved.