A new synthetic route to hollow Co3O4 octahedra for supercapacitor applications

Co3O4 hollow octahedra were successfully synthesized via a facile one-step solvothermal route. Time-resolved electron microscopy and X-ray diffraction analyses revealed that the Co3O4 hollow octahedra were formed through the self-assembly of primary nanocrystals followed by subsequent Ostwald ripening. Subtle control over the reaction conditions led to different morphologies (hexagonal plates and nanocubes) and crystal structures (beta-Co(OH)(2)-Co3O4 composite). The unique hollow nanostructure rendered our Co3O4 potentially useful for charge-storage applications. To prove its usefulness, the pseudocapacitive performance of the Co3O4 hollow octahedra as a supercapacitor electrode was evaluated and exhibited a charge storage capacity of 192 F g(-1) with good long-term cyclability.