Synthesis of dodecanethiol monolayer-stabilized nickel nanoparticles

Nickel nanoparticles surface-capped with self-assembled monolayer of dodecanethiol were prepared by the controlled reduction of nickel chloride (NiCl2·6H2O) in the presence of dodecanethiol of different concentrations as the ligand and hydrazinium hydroxide as the reductant. The morphology and structure of the resulting surface-capped nickel nanoparticles were analyzed by means of transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transformation infrared spectroscopy and thermogravimetric analysis. It was found that dodecanethiol played a critical role in controlling the radius and dispersibility of the surface-capped Ni nanoparticles. Namely, the nickel nanoparticles prepared in the absence of the surface-capping agent were liable to aggregate, while those prepared in the presence of decanethiol with a large enough concentration had a very small grain size. It was supposed that the surface-capped nickel nanoparticles with significantly increased stability and dispersibility as compared to the non-surface-capped nickle nanoparticles could be used as a kind of novel nanoscale lubricating additives.