Solvothermal synthesis of Cu-doped Co 3 O 4 nanosheets at low reaction temperature for potential supercapacitor applications

Cu-doped Co3O4 (1, 3, 5 and 7 wt%) nanoparticles were synthesized through the decomposition of cobalt (II) acetylacetonate, cobalt (III) acetylacetonate and copper (II) acetylacetonate in the least toxic polar solvent through solvothermal method. XRD analysis confirmed the formation of cubic spinel structure with reduced crystallite size of 20 nm and slight lattice expansion upon Cu doping. The spectral analysis carried out by FTIR and Raman studies expressed the existence of functional group and active vibrational modes. UV–Vis analysis revealed the increase in bandgap value with increasing dopant concentration. Slightly dissociated nanosheets and cubic structure were observed in HR-SEM and HR-TEM analyses with an average particle size of 25 nm. SAED pattern indicated the polycrystalline nature of the synthesized nanoparticles. The weak ferromagnetic nature with low coercivity and remanent ratio is deliberated from magnetic measurement. The Cu dopant was found to enhance the electrochemical performance of Co3O4 nanoparticles with high specific capacitance, since it possesses larger surface area due to reduced particle size.