In this paper, preparation of ultrathin willow-like CuO nanoflakes via a one-step process was reported. Xray diffraction pattern showed the formation of monoclinic CuO crystal, which was also confirmed by result of high resolution transmission electron microscopy. Scanning electron microscopy showed that ultrathin willow-like CuO nanoflakes were formed. Catalytic testing indicated that the ultrathin willow-like CuO nanoflakes exhibited high electrocatalytic activity and durability toward the electro-oxidation of hydrazine in alkaline medium. The results suggested that the as-prepared CuO nanoflakes were potential electrode materials for hydrazine fuel cell. (C) 2015 Elsevier B.V. All rights reserved.