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.