Nickel nanoparticles are used as a catalyst to produce various substances — for example, synthetic hydrocarbons. Broad use of this inexpensive catalytic metal is limited by the fact that researchers have no effective method of generating nanoparticles of similar structure and of closely varied sizes.

Experts at the Nanotechnologies and Nanomaterials Research Centre at Tambov Derzhavin State University have suggested making nickel nanoparticles of a certain size using metal precipitation on carbon nanotubes — as some “scaffolding” for nickel nanoparticles. The research report was published in the Letters of Technical Physics Journal. The study was supported by the Federal Task Program “Scientific and Pedagogical Resources of Innovative Russia, and the Analytic Departmental Task Program “The Development of Scientific Potential of Higher School of Education.”

The nanoparticles were generated by galvanic chemical precipitation (the effect of electric field on nickel-containing electrolyte). Nanotube water suspension was put on the polished surface of the copper cathode in advance. After the water dried out, carbon nanotubes were left on the cathode surface, with nickel precipitating of them later. The structure of the resultant particles was studied using an electronic microscope.

Nickel nanoparticles precipitated mainly on various defect parts of the nanotubes, as well as on their ends. In the course of the growth process, the nickel nanoparticles formed “beads” on the carbonic nanotubes. The acquired structure consisted of nickel nanoparticles situated on the carbonic nanotubes frame, with a slight variation to the particle sizes. The researchers noted that the mass of carbon nanotubes with the nickel particles applied on them was highly transparent for a flow of fluid or gas, unlike common nickel particle powder. This allows an assumption that the catalytic activity of the nickel particles applied on the nanotubes can be more significant.

The cost price of carbonic nanotubes is still rather high and therefore the researchers have conducted a preliminary cost-effectiveness assessment of the nanotube usage as a frame for nickel catalyst. It was proved that the total area of the nickel nanoparticles is twice as large as the nanotube surface or more. That justifies the use of carbonic nanotubes as “scaffolding” for nickel nanoparticles.

The proposed structure will be able to broaden the use of the nanotubes as well — as bioactive materials, for example. Nanotubes can be easily absorbed by cells and therefore can serve as transport for various molecules necessary for treatment and diagnostics. Nickel magnetic properties can help in developing the methods for target medicine delivery into the cells, and the increase of the total surface will allow to “load” the nanotube with more molecules.

Dmitry Tsendin