Catalytic behavior of nickel nanoparticles stabilized by lower alkylammonium bromide in aqueous medium

Heterogeneous synthesis of monodisperse pure nickel nanoparticles in aqueous medium has been carried out using cetyltrimethylammonium bromide and a lower alkylammonium bromide mixture of tetraethylammonium bromide and tetrabutylammonium bromide. The presence of cetyltrimethylammonium bromide alone results in the formation of a mixture of nickel hydroxide and nickel nanoparticles. The particles have been characterized using TEM, EDS, XRD, TGA–DSC and FTIR. The analysis showed that particles are spherical in shape, monodisperse, face-centered-cubic with average size about 15 nm and are stable in air up to 325 °C. The nanoparticles have been used as a solid phase catalyst for the reduction of p-nitrophenol in the presence of hydrazine hydrate as reducing agent at different temperatures under varying conditions. The reduction process has been monitored by UV–vis analysis. The present study showed that nanoparticles are not poisoned after their repeated use in reduction of p-nitrophenol to p-aminophenol. TEM analysis also confirms that nanoparticles are stable in the dispersed medium for longer times.

Heterogeneous synthesis of monodisperse nickel nanoparticles in aqueous medium carried out using cetyltrimethylammonium bromide and lower alkylammonium bromides. The particles were characterized using TEM, EDS, XRD, TGA–DSC and FTIR. The particles are spherical in shape, fcc with average diameter 15 nm, stable in air up to 325 °C. Nanoparticles have been used as a solid phase catalyst for the reduction of p-nitrophenol using hydrazine hydrate as reducing agent under different conditions. The reaction mechanism was monitored with UV–vis spectrophotometer. The particles were not poisoned after repeated use. Figure optionsDownload as PowerPoint slide