PRECIPITATION OF NICKEL-CONTAINING PARTICLES FROM NICKEL NITRATE SOLUTIONS UNDER THE ACTION OF A DIRECT CURRENT GLOW DISCHARGE

Abstract

In this paper we present the results on the synthesis of nickel-containing particles from solutions of nickel nitrate under the action of a DC glow discharge at atmospheric pressure in air. The interaction of the plasma with the solution leads to the formation of a colloidal suspension in the anode part of the cell, followed by the formation of agglomerates and precipitation to the bottom of the cell. The composition and surface structure of the resulting powders were studied using scanning electron microscopy, Brunauer–Emmett–Teller analysis, X-ray diffraction analysis, X-ray energy-dispersive spectroscopy, and thermogravimetric analysis. According to the results of dynamic light scattering, particles in solution have two characteristic sizes of the order of 73.5 nm and 1.2 μm. Images obtained on a scanning electron microscope showed that the resulting powders have a well-developed granular structure. X-ray phase analysis of the obtained samples showed the presence of clearly defined reflections, which indicate the crystallinity of the structure of the synthesized powder. Decoding showed that it is β-type nickel hydroxide. The elemental composition of the surface obtained using X-ray energy-dispersive spectroscopy showed the presence of nitrogen in the sample. Therefore, the powders have a complex composition and are a mixture of hydroxide and hydroxonitrate with a ratio of 0.8 Ni(OH)2 : 0.2 Ni(OH)NO3. Thermogravimetric analysis confirms the data obtained using X-ray energy dispersive spectroscopy. High-temperature treatment of the obtained powders leads to the formation of β-type nickel oxide. The specific surface area (Ssp) was calculated using the Brunauer–Emmett–Teller method from the adsorption branch in the range of relative pressures of 0.05–0.20; the total pore volume (Vp) and pore size distribution were calculated from the desorption branch in the range of 0.40–0.99.