Synthesis of nickel nanoparticles on multi-walled carbon nanotubes by gamma irradiation

• Nickel nanoparticles were deposited on multi-walled carbon nanotubes by gamma irradiation.
• The effect of dose on size distribution of the nanoparticles was evaluated.
• Between 30 and 60 kGy, as dose increases the average size of the nanoparticles decrease from 16 to 12 nm.

Multi-walled carbon nanotubes (MWCNTs) were used as a substrate for nickel nanoparticles production. Nickel nanoparticles of average sizes between 9 and 16 nm were synthesized by gamma irradiation of aqueous solutions containing nickel sulfate or nickel chloride as precursors. MWCNTs were acid treated and poly vinyl pyrrolidone (PVP, m∼44,000) or sodium dodecyl sulfate (SDS) were used as stabilizers. Isopropanol was used as a scavenger of hydroxyl radicals, and deionized (DI) water as a solvent. Gamma irradiation was carried out at room temperature and ambient pressure in a 60Co gamma source at doses of 30, 40, 50, and 60 kGy. The nickel nanoparticles were characterized by transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and X-ray photoelectron spectroscopy (XPS). By controlling the dose and stabilizer's concentrations, nanoparticles with different sizes were obtained. Poly vinyl pyrrolidone (PVP) was found to be more efficient at preventing coalescence of Ni seeds than sodium dodecyl sulfate (SDS).