3D hierarchical Co3O4: Controlled preparation of coral-/urchin-like structures and application in photo-catalytic degradation

Three-dimensional (3D) hierarchical architectures built from spherical assembly of nanowires/nanorods have found applications in a wide range of fields. However, although some literatures have reported their successful preparation, up to now, it is difficult to adjust the size of the building blocks of the 3D structures, which indeed largely affects the performance of the materials. In this work, by adopting metal ions and PVP modified carbon spheres as templates, we demonstrate a seed-mediated growing strategy to control Co3O4 shapes to be 3D urchin-like hierarchical structures constructed from 40 nm-diameter nano-wires, or 3D coral-like ones assembled from thicker 100 nm-diameter nano-rods. XRD patterns show both structured Co3O4 are cubic phase, and N-2 sorption demonstrates they own both mesopores and macropores. Besides, the obtained materials display good photocatalytic performance and reusability to degrade Congo Red dye. (C) 2017 Elsevier B.V. All rights reserved.