A facile chemical route for synthesis of nitrogen-doped graphene aerogel decorated by Co3O4 nanoparticles

Abstract

Production of metallic oxide/graphene aerogel composite systems is of great importance regarding their superb electrochemical and adsorption characteristics. Developing a facile and economic synthesis route is a necessity for thriving exploitation especially when the synthesis process has to compete with other chemical/physical synthesis processes. In the present work, nitrogen doped cobalt oxide/graphene aerogel nanocomposite (N-doped Co3O4/GA) was successfully synthesized via a facile, cost-effective and environmentally friendly route. In this mild chemical reduction based route, the pre-adsorbed GO solution was exposed to L-Ascorbic Acid (LAA) that acted both as the reducing agent and cross-linker. In order to incorporate nitrogen atom within the nano-composite structure, ammonium solution was added to the prepared cobalt–graphene hydrogel (GH); this resulted in doping of the nitrogen atoms as well as strengthening of the composite. The freeze drying process was then conducted to convert the prepared N-doped cobalt–GH to N-doped cobalt–GA and finally, N-doped Co3O4/GA was obtained after heat treatment. The formation of Co3O4 was confirmed by X-Ray diffraction analysis and according to microscopic images, the spherical Co3O4 nanoparticles were randomly distributed over the graphene sheets with a size distribution of 8–10 nm. In addition, the BET specific surface area and the pore volume of composite were estimated 215 m2 g−1 and 1.22 cm3 g−1, respectively. Moreover, the bulk density was 19 mg cm−3 and the load bearing limit of N-doped Co3O4/GA was higher than 2000 times of its own weight. Due to the excellent mechanical strength as well as favorable density, the synthesized nano-composite system can be promisingly a preferred candidate for the electrode materials in the energy storage devices.