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Journal №4 for 2015 г.
Article in number:
Nanotubes sodium-vanadium oxide bronzes as effective centers of surface ionization of molecules of nitrocompounds
Keywords: nanotubes sodium-vanadium oxide bronze surface ionization nitrocompounds mass-spectrometry ion current surface ionization efficiency the activation energy of surface ionization
Authors:
V.I. Kapustin - Dr.Sc. (Phys.-Math.), Professor, Moscow State University of Information Technologies, Radioengineering and Electronics. E-mail: kapustin@mirea.ru A.P. Korzhavyi - Dr.Sc. (Tech.), Professor, Kaluga Department of the Bauman State Technical University. E-mail: fn2kf@list.ru A.K. Zakharov - Ph.D. (Tech.), Professor, Moscow State University of Information Technologies, Radioengineering and Electronics. E-mail: zakharovak38@mail.ru D.V. Kapustin - Ph.D. (Phys.-Math.), Leading Engineer, OAC MGTS (Moscow). E-mail: kapustin01@mail.ru
Abstract:
The crystal structure of sodium - vanadium oxide bronze composition Na0,33V2O5 in the existence of β-phase has a monoclinic structure in the form of nanotubes along the axis b, which are located in the chain of sodium ions - two for each unit cell. At each unit cell, there are three equivalent positions that can be occupied by sodium ions. The composition of the oxide bronze Na0,33V2O5 sodium ions can be orderly placed on these equivalent provisions. In the event the composition of the oxide bronze from stoichiometric composition, for example in bronze composition Na0,28V2O5, sodium ions are characterized by high mobility along the axis b. In the adsorption on the surface of the oxide bronze molecules of nitro compounds, which include a nitro group - NO2, with significant dipole moment, said nitro can capture sodium ion to form stable ionic complex R-NO2-Na+, where R - an organic radical. In the temperature range 300-600 °C such a complex can be desorbed from the surface of the oxide bronze, thus realizing the selective superficial ionisation of molecules of nitrocompounds. We studied the parameters of the crystal structure of sodium-vanadium oxide bronze NaхV2O5 in the range x = 0,22-0,33 and found that when x = 0,28 the volume of the unit cell is the minimum value that indicates the ordering in the lo-Annex sodium ions in the chain of elementary cells and for a given parameter x. By mass spectrometry to study the composition of high resolution background ion current from the surface of the sodium vanadium oxide bronzes under the conditions of air at atmospheric pressure. It was found that the main ions are desorbed from the surface of the bronze in the temperature range 300-600 °C are clusters based on sodium ions captured water molecules and clusters on the basis of potassium ions from the microimpurities in bronze, also capture water molecules. The method of mass spectrometry, high-resolution established that the main types of ions produced by ionization of molecules of nitro compounds on the surface of the oxide bronze, are clusters based on organic molecules captured sodium ions and molecules of oxen from the air. Measurements of the ionization efficiency of nitrocompounds on the surface of the oxide bronzes confirmed the maximum effect of a single crystal structure bronze Na0,28V2O5.
Pages: 34-42
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