Growth of a Carbon Micro- and Nanocoils Mixture using NiSO4 as the Catalyst Precursor

A mixture of carbon micro- and nanocoils (CMCs/CNCs) is synthesized by catalytic pyrolysis of acetylene at 650 °C using NiSO₄ as the catalyst precursor. The morphology of the grown product is analyzed by scanning electron microscopy (SEM). Experimental results indicate that, in general, the CMCs are in double-helical form, while most of the grown CNCs are in twisted single-helical form. The coil diameters of CMCs and CNCs are approximately 4 to 10 mm and 300 to 400 nm, respectively. Raman spectra indicate that the real active catalyst precursor for growing CMCs/CNCs is NiSO₄, while NiO is not an effective catalyst precursor for synthesizing CMCs or CNCs.