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Editorial

Rudowicz Cz., Sojka Z., Jezierska J., Pietrzyk P.

Nukleonika

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2015

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Vol. 60, No. 3, part 1

375

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Interaction of diatomic molecules with nickel ions inside the channels of high silica zeolites : an EPR and DFT study

Mazur T., Podolska K., Pietrzyk P., Sojka Z.

Nukleonika

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2013

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Vol. 58, No. 3

351--357

EN

Interaction of CO, NO, and O2 diatomics with NiII and NiI ions dispersed in ZSM-5 zeolite was investigated by electron paramagnetic resonance (EPR) spectroscopy and density functional theory (DFT) modelling. The resulting adducts NiI-CO, NiII-NO, and NiI-O2 were identified based on g-tensor parameters, obtained by computer fitting of the powder EPR spectra, and next ascertained by parallel relativistic DFT calculations of the corresponding g-tensor values. The structures of the NiI-CO, NiII-NO, and NiI-O2 complexes were obtained by geometry optimization with the Kohn- -Sham method. Binding of the diatomics was discussed in terms of the spin-pairing and electron density transfer events. Interaction of CO with NiI cations led to the pronounced change in the coordination and electronic structure of the NiI center, however, no redox processes were observed in agreement with the “innocent” nature of CO as a ligand. On the contrary, strong electron and spin density redistribution was observed upon NO and O2 interaction (“non-innocent ligands”) leading to the formation of the bound nitrosonium NOδ+ and superoxo O2 – species, respectively.

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Katalizator do niskotemperaturowego rozkładu tlenku azotu(I) ze strumienia gazów resztkowych z instalacji kwasu azotowego

Inger M., Saramok M., Wilk M., Stelmachowski P., Zasada F., Maniak G., Piskorz W., Adamski A., Kotarba A., Sojka Z., Granger P.

Przemysł Chemiczny

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2009

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T. 88, nr 12

1307-1313

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Structural and textural evolution of zirconia nanocrystals induced by thermal treatment

Adamski A., Jakubus P., Sojka Z.

Materials Science Poland

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2008

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Vol. 26, No. 2

373--380

EN

Nanometric tetragonal and monoclinic zirconia was synthesized from zirconyl chloride by the modified forced hydrolysis method. Phase transitions and morphological changes accompanying zirconia calcination in the temperaure range 600-1000 °C were studied by XRD, HR-TEM techniques and N2-porosimetry. Ageing of the amorphous hydrous zirconia at 100 °C for 48 h in the mother solution and its subsequent calcination at 600 °C for 6 h strongly favoured formation of single-phase tetragonal ZrO2 of the thermal stability enhanced by 250 °C. Influence of the calcination temperature on phase composition, grain size, grain boundaries and pore structure of the resultant ZrO2 material was analyzed.

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Promotory alkaliczne na powierzchniach katalitycznych : od badań modelowych do stosowanych

Kotarba A., Rożek W., Kruk-Serafin I., Sojka Z.

Przemysł Chemiczny

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2006

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T. 85, nr 8-9

741-743

PL

Przedstawiono w formie krótkiego przeglądu zastosowanie metody termicznej desorpcji metali alkalicznych do określania statusu promotorów alkalicznych na powierzchniach katalitycznych. Pomiary przeprowadzono w warunkach wysokiej próżni, in-situ w przepływie reagentów oraz z modulacją potencjału elektrycznego próbki. Badaniami objęto zarówno układy modelowe, jak i katalizatory przemysłowych procesów produkcji amoniaku, styrenu, reformingu parowego oraz hydroodazotowania i hydroodsiarczania.

EN

A review with 16 refs. covering appln. of the species resolved thermal alkali desorption (SR-TAD) technique to detg. the alkali promoter status on the catalyst surface. High-vacuum in-situ SR-TAD detns. run with the reactants flowing and the elec. field modulated at the surface, comprised model and com. catalyst systems for making ammonia, styrene, and for steam reforming and deep hydrotreatment.

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Synthesis of nanostructured tetragonal ZrO2 of enhanced thermal stability

Adamski A., Jakubus P., Sojka Z.

Nukleonika

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2006

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Vol. 51,suppl.1

27-33

EN

Hydrous zirconia particles of nanometric dimensions were synthesized via forced hydrolysis of zirconyl chloride. Prolonged aging at 100°C in the mother liquor and subsequent calcination produced a single-phase tetragonal ZrO2 of enhanced thermal stability with the narrow size and pore distributions. The influence of the preparation conditions on the phase composition of the resultant zirconium dioxide was examined using structural (XRD, SEM/TEM) and spectroscopic (Raman) methods, supported by thermal analysis (DTA/TG, DSC) and N2-porosimetry. The nature of the parent salt, pH of the solution, the temperature of precipitation and aging, were found to be the key parameters of the successful synthesis. The sequence of mechanistic steps invoked to account for the formation of t-ZrO2 was rationalized using the concepts of zirconium aquatic chemistry.

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Electron paramagnetic resonance investigations of CO adsorption on RuY zeolite

Blasco T., Bonneviot L., Li X. W., Che M., Chaquin P., Clerjaud B., Sojka Z.

Bulletin of the Polish Academy of Sciences. Chemistry

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2002

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Vol. 50, No. 2

267-279

EN

The adsorption of carbon monoxide onto ruthenium exchanged into NaY zeolite has been investigated by CW-EPR techniques using (13) C-enriched CO. A low spin eta (1){Ru(3cCO}(5) adduct with g = 2.065, g\\ = 1.987 and |A((99)Ru) = 1.3 mT, |A||(99)Ru) = 1.7 mT, |A_|(101 Ru) = 1.5 mT, A||(101)Ru) = 1.9 mT and |A|(13)C) = 6.0, |A|| |(13)C) = 6.8 mT has been identified. The magnetic parameters have been analyzed in terms of the molecular structure and spin density distribution. The results are consistent with an apical coordination of CO and the bonding established by the overlap between d(z)z2 and 5 sigma orbitals. The eta{RuIII (3c)CO}(5) adduct can be classified as a a metal-centred radical located in SIl'/SII sites. The spin density on Ru is equal to 0.6 and is confined mainly to the dz(2) orbital and 0.1 on carbon atom of the CO ligand.

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Spectroscopic study of hydroxymethyl radicals produced on MoOx/SiO2 catalysts by interaction of methanol with UV-induced [Mo5+--O-] triplet state

Sojka Z., Che M.

Bulletin of the Polish Academy of Sciences. Chemistry

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2000

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Vol. 48, No. 4

313-324

EN

EPR along with MAS-NMR and QM spectroscopy have been used to investigate the structure and reactivity of hydroxymethyl radicals formed upon UV -irradiation of methanol adsorbed on MoOx /Si0(2) catalysts. The use of natural and 13C-enriched methanol allowed the authors to ascertain the 1 H superhyperfine and 13C hyperfine tensors. Based on the analysis of the magnetic parameters the structure of .CH2OH radical interacting with the catalysts has been determined: it is non-planar and the c- H bonds are stretched. The hydroxymethyl intermediates were found to reduce surface Mo(6+) centers and adsorbed O2 via an electroprotic mechanism involving electron transfer and release of the hydroxyl proton.