A facile method to fabricate porous Co3O4 hierarchical microspheres

Flower-like Co3O4 hierarchical microspheres composed of self-assembled porous nanoplates have been prepared by a two-step method without employing templates. The first step involves the synthesis of flower-like Co(OH)2 microspheres by a solution route at low temperatures. The second step includes the calcination of the as-prepared Co(OH)2 microspheres at 200 °C for 1 h, causing their decomposition to form porous Co3O4 microspheres without destruction of their original morphology. The samples were characterized by scanning electron microscope, transmission electron microscope, X-ray diffractormeter and Fourier transform infrared spectroscope. Some experimental factors including solution temperature and surfactant on the morphologies of the final products have been investigated. The magnetic properties of Co3O4 microspheres were also investigated.

Graphical AbstractFlower-like Co3O4 microspheres are composed of self-assembled nanoplates and these nanoplates appear to be closely packed in the microspheres. These nanoplates consist of a large number of nanocrystallites less than 5 nm in size with a porous structure, in which the connection between nanocrystallites is random.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch Highlights► Flower-like Co3O4 hierarchical microspheres composed of self-assembled porous nanoplates have been prepared by a two-step method without employing templates. ► Layered Co(OH)2 microspheres were prepared with an appropriate approach under low temperatures for 1 h reaction. ► Calcination caused Co(OH)2 decomposition to form porous Co3O4 microspheres without destruction of their original morphology.