A 3D nanosponge-like NiOOH/Ni(OH)(2) film, showing inherent switchable wettability and high compatibility with different electrolytes, is demonstrated to be a suitable template for synthesizing metal nanoparticles with different sizes (from nanoscale to submicroscale range) and diverse shapes (from spherical to branched nanostructures). The rich nanostructures, including peapod-like, spherical, and dendritic nanocomposites, exhibit different optical responses. Furthermore, the nanoparticles are easily isolated from the template in a non-destructive manner and well-dispersed in the acidic environment with good uniformity. (C) 2016 Elsevier B.V. All rights reserved.