Synthesis and electrochemical capacitive behaviors of Co3O4 nanostructures from a novel biotemplating technique

A novel approach is developed to synthesize Co3O4 nanoparticles utilizing sawdust as a bio-template. Sawdust was first infiltrated with cobalt dichloride aqueous solution, and then, in situ precipitation reaction took place when different precipitators (NaOH or H2C2O4) were added. Finally, the precursors, Co(OH)2 and CoC2O4, were calcined to produce the final Co3O4 nanoparticles and the template was removed simultaneously. The structure and morphology of the obtained products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy. The observations revealed the formation of cubic phase Co3O4 with the average diameter of about 40 and 60 nm, respectively. Their electrochemical properties were investigated by cyclic voltammetry and galvanostatic charge–discharge tests. The highest specific capacitance of 289.7 F g−1 for the obtained Co3O4 electrode was obtained even at a discharge current of 20 mA after the 100th cycle and it increased by about 4% after the 1,000th cycle, demonstrating good electrochemical stability of such electrode materials.