Synthesis and magnetic properties of nanoporous Co3O4 nanoflowers

Nanoporous Co3O4 hierarchical nanoflowers have been prepared through sequential process of a hydrothermal reaction and heat treatment. These nanoflowers consisting of a great deal of Co3O4 nanofibers have bimodal pore structures and Brunauer–Emmett–Teller surface area of ∼34.61 m2/g. The temperature dependence curves of magnetization in zero-field-cooled and field-cooled exhibit main antiferromagnet and weak ferromagnet of Co3O4 nanoflowers at blocking temperature of ∼34 K, respectively. In addition, analysis of their optic properties obviously indicates red shift of absorption peaks, exhibiting quantum-confined effect and traits of semiconductor.