Without any capping agent, surfactant or external magnetic field, hierarchical nickel was successfully prepared via a simple hydrothermal reduction method by using hydrazine hydrate as reducing agent. The structure and morphology of the products (for instance, flower-like, column-like and spherical-like) were controlled by adjusting hydrothermal conditions including reaction temperature and solvent. The morphology transformation mechanism was proposed and discussed. Corresponding platinum/nickel catalysts (Pt/Ni) were obtained by the galvanic replacement reaction method. And the catalytic activity of the platinum/nickel samples was evaluated by using selective hydrogenation of nitrobenzene. It was found that platinum/flower-like nickel showed the most excellent catalytic performance among the as-synthesized catalysts in this work, with good stability as well. Moreover, reasons for the enhancement of platinum/flower-like nickel for nitrobenzene hydrogenation were investigated. (C) 2017 Published by Elsevier B.V.