Facile and green synthesis of mesoporous Co3O4 nanocubes and their applications for supercapacitors

Abstract

Nanostructured Co₃O₄ materials attracted significant attention due to their exceptional electrochemical (pseudo-capacitive) properties. However, rigorous preparation conditions are needed to control the size (especially nanosize), morphology and size distribution of the products obtained by conventional methods. Herein, we describe a novel one step shape-controlled synthesis of uniform Co₃O₄ nanocubes with a size of 50 nm with the existence of mesoporous carbon nanorods (meso-CNRs). In this synthesis process, meso-CNRs not only act as a heat receiver to directly obtain Co₃O₄ eliminating the high-temperature post-calcination, but also control the morphology of the resulting Co₃O₄ to form nanocubes with uniform distribution. More strikingly, mesoporous Co₃O₄ nanocubes are obtained by further thermal treatment. The structure and morphology of the samples were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. A possible formation mechanism of mesoporous Co₃O₄ nanocubes is proposed here. Electrochemical tests have revealed that the prepared mesoporous Co₃O₄ nanocubes demonstrate a remarkable performance in supercapacitor applications due to the porous structure, which endows fast ion and electron transfer.