Synthesis, characterization, and cyclic voltammetry of nickel sulphide and nickel oxide nanoparticles obtained from Ni(II) dithiocarbamate

Nickel sulphides and nickel oxides nanoparticles have been synthesized from Ni(II) bis (N-alkyl-N-ethanoldithiocarbamate), represented as NiL21 (L-1, with methyl group) and NiL22 (L-2, with ethyl group). Both complexes were characterized using Fourier transform infra-red (FTIR), nuclear magnetic resonance spectroscopy and elemental analysis. The sulphides were prepared by solvothermal route in hexadecylamine, and X-ray diffraction analyses revealed that Heazlewoodite Ni3S2 and hexagonal alpha-NiS1.19 were the phases obtained from compounds Ni-2(1) and NiL22 respectively. The nickel oxides nanoparticles were synthesized via calcination process in air, and presented as NiO1 and NiO2 of which both oxides are Bunsenite phase. The optical and morphology of the nanoparticles were studied using UV-visible spectroscopy and transmission emission microscopy (TEM) techniques. Cyclic voltammetry (CV) and impedance spectroscopy were used for their electrochemical evaluation in 1 M NaOH solution. The Au/NiO2 modified electrode was more electroactive and displayed faster electron transport at the electrode surface than the bare Au and Au/NiO1 electrodes. The modified Au/NiS electrode, showed poor voltammogram which could be due to the poor interaction between the nanoparticles and the electrolyte solution, while the CV of uncapped NiS showed redox peak with oxidation peak potential at 0.36 V and the reduction peak potential at 0.30 V.