LAUSR

Abstract This work presents a novel synthesis of a nickel complex to fabricate Ni-pillared clay (Ni-PILC) as the supporting catalyst for the synthesis of carbon nanotubes (CNTs). To identify the synthesized complex structure, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), elemental analysis, and X-ray photoelectron spectroscopy (XPS) were applied to propose the hexanuclear acetato-ammonia nickel(II) acetate complex, with the chemical formula of [Ni6(OOCCH3)11(NH3)·7H2O]+(OOCCH3)−. Various concentrations of the nickel complex (0.5, 1, 2, 3, 4, 5, 6, 7, and 8 CECs) were used to instigate the ion exchange reaction with the montmorillonite (Mt) surface. Chemical vapor deposition was used to synthesize CNTs. XRD, TGA, Raman, SEM, and TEM characterizations were performed on the CNTs to investigate the influence of the catalyst concentration on the properties of CNTs. Depending on the catalyst concentration, the mass loss of CNTs varied from 28% at 0.5 CEC of the Ni catalyst to ~70% at 8 CEC of the Ni complex. XRD indicated that Na+Mt. layers were intercalated with nickel species during the ion-exchange processes, and then delaminated due to the growth of CNTs. The introduction of higher concentrations of the nickel salt into Mt. improved the quality and the synthesis yield.