Growth control of cobalt oxide nanoparticles on reduced graphene oxide for enhancement of electrochemical capacitance

Effat Jokar, Azam Iraji zad, Saeed Shahrokhian*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The high capacitance and cyclic stability of graphene nanosheets decorated with Co3O4 nanoparticles as a material for supercapacitor electrodes are reported here. Hydrothermal method is adopted to deposit cobalt oxides on the reduced graphene oxide (RGO) sheets in a mixture of water and dimethylformamide (DMF) as the solvent with different volume ratios. The water volume ratio presents a crucial factor in the nucleation and growth process. In addition, it affects dispersion, particle size and the amount of nucleated cobalt oxide particle on the graphene sheets. By decreasing the water volume, the nucleation and growth occur mainly on graphene rather than in solution. According to the obtained results from transmission electron microscopy, scanning electron microscopy and thermogravimetric analysis, a model for growth of nanoparticles on graphene sheets is proposed. Based on the obtained results, the presented model can also be used for the synthesis of other graphene-metal (oxide) composites. Electrochemical measurements indicate that water volume ratio in the mixture solvent influences on capacitance of the RGO/Co3O4 composite electrodes. The highest obtained specific capacitance is 440.4 F g−1 with 50% volume ratio of water at current density of 5 A g−1.

Original languageEnglish
Pages (from-to)21068-21075
Number of pages8
JournalInternational Journal of Hydrogen Energy
Issue number36
StatePublished - 12 Dec 2014


  • Cobalt oxide nanoparticles
  • Nucleation and growth
  • Reduced graphene oxide
  • Solvent effect
  • Supercapacitors

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