| 1. |
- Fionov, A.V., et al.
(författare)
-
Paramagnetic centers in detonation nanodiamonds studied by CW and pulse EPR
- 2010
-
Ingår i: Chemical Physics Letters. - : Elsevier Science B.V., Amsterdam.. - 0009-2614 .- 1873-4448. ; 493:04-Jun, s. 319-322
-
Tidskriftsartikel (refereegranskat)abstract
- Dispersed detonation nanodiamonds have been studied by continuous-wave (CW) and pulse EPR techniques. The spectrum of bulk radicals (g = 2.0025 +/- 0.0002, a Lorentz line shape with Delta H-pp = 0.95 +/- 0.05 mT) dominated in CW EPR and prevented to record spectra from other paramagnetic species. The pulse EPR-spectrum was the superposition of the distorted P1-center spectrum with parameters (g = 2.0025, A(xx) = 2.57 mT, A(yy) = 3.08 mT, A(zz) = 4.07 mT), the H1-center spectrum (g = 2.0028) and the single line (g = 2.0025, DHpp = 0.40 +/- 0.05 mT) from other centers which may be assigned to surface radicals. The concentration of P1-centers has been estimated by CW EPR as 2 +/- 1 ppm N.
|
|
| 2. |
- Tveritinova, E A, et al.
(författare)
-
Catalytic conversion of C(2)-C(3) alcohols on detonation nanodiamond and its modifications
- 2012
-
Ingår i: Russian Journal of Physical Chemistry. - : MAIK Nauka/Interperiodica. - 0036-0244 .- 1531-863X. ; 86:1, s. 26-31
-
Tidskriftsartikel (refereegranskat)abstract
- The catalytic activity of detonation nanodiamond and its modifications obtained through treatment with hydrogen or air at elevated temperatures is studied in the conversion of C(2)-C(3) alcohols. The catalysts were characterized by means of electron microscopy, optical (FTIR) spectroscopy, elemental analysis and pulse microcatalytic method. It has been established that nanodiamond exhibits high catalytic activity in the conversion of alcohols. The oxidizing and reducing treatment of nanodiamond changes its activity and selectivity, and the activity of oxidized nanodiamond is considerably higher than that of reduced nanodiamond.
|
|
| 3. |
- Tveritinova, E. A., et al.
(författare)
-
Effect of the detonation nanodiamond surface on the catalytic activity of deposited nickel catalysts in the hydrogenation of acetylene
- 2013
-
Ingår i: Russian Journal of Physical Chemistry. - : SP MAIK Nauka/Interperiodica. - 0036-0244 .- 1531-863X. ; A 87:7, s. 1114-1120
-
Tidskriftsartikel (refereegranskat)abstract
- A comparative study is performed of the catalytic activity of nanosized nickel deposited on deto nation synthesis nanodiamond (DND) and coal (CSUG) produced by burning sugar and crystalline quartz in the hydrogenation of acetylene. Nanosized nickel is obtained through the thermal decomposition of nickel formate under a dynamic vacuum. The catalysts are studied by means of scanning electron and transmission electron microscopy, Xray fluorescence, IRspectroscopy, Xray diffraction, and pulse microcatalytic method. It is shown that Ni/DND is an active catalyst of acetylene hydrogenation, considerably surpassing Ni/quartz and Ni/CSUG. The apparent activation energy of the hydrogenation of acetylene is calculated, and the region of the reaction are determined for all catalysts. It is found that the influence of the structure and nature of a functional coating of nanodiamond on the catalytic activity of Ni/DND deposited catalyst in the hydrogenation of acetylene. The ability of Ni/DND to hold active hydrogen is detected.
|
|
| 4. |
- Baranov, A. I., et al.
(författare)
-
2D metal slabs in new nickel-tin chalcogenides Ni(7-delta)SnQ(2) (Q=Se, Te) : average crystal and electronic structures, chemical bonding and physical properties
- 2004
-
Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 177:10, s. 3616-3625
-
Tidskriftsartikel (refereegranskat)abstract
- A systematic search for mixed low-valence, nickel-tin chalcogenides performed by establishing phase relations in the parts of Ni-Sn-Se and Ni-Sn-Te ternary systems resulted in the discovery of two new compounds, Ni5.62SnSe2 and Ni5.78SnTe2 Single crystals of both compounds were prepared by chemical transport with iodine and crystal structures were determined by single crystal X-ray investigation. The ED patterns for Ni5.78SnTe2 showed the presence of satellite reflections, which indicate a modulated structure with qapproximate to0.4a*. Average crystal structures of both compounds were determined to be of tetragonal symmetry (Sp.gr.I4/mmm, Z = 2) with a = 3.6890(8) Angstrom, c = 18.648(3) Angstrom, R-w = 0.0716 and a = 3.7680(5) Angstrom, c = 19.419(4) Angstrom, R-w, 0.0832, correspondingly, and are isostructural to known Ni5.72SbSe2 and Ni5.66SbTe2. Measurements were carried out for both compounds with respect to thermal, electrical and magnetic properties. Ab initio band structure calculations were also performed to take a first glance into the electronic structure of such type compounds. The anisotropy of their band structure was found. Physical property measurements showed both compounds to be the anisotropic metallic conductors and paramagnetics. Calculated difference charge density maps revealed pairwise covalent and multicenter metallic nature of the d-metal-chalcogen and d-metal-p-metal interactions, respectively.
|
|
