Professor Vladimir Zaitsev

D.Sc., PhD, Corr. member of Acad. of Sci. of Ukraine

2005

  1. Lysenko,V.; Bidault,F.; Alekseev,S.; Zaitsev V., Barbier,D.; Turpin,C.; Geobaldo,F.; Rivolo,P.; Garrone,E.
    Study of Porous Silicon Nanostructures as Hydrogen Reservoirs.
    Journal of Physical Chemistry B, 2005; 109(42); 19711-19718
    The amount of hydrogen present in porous silicon (PS) nanostructures is analyzed in detail. Concentration of atomic hydrogen chemically bound to the specific surface of PS is quantitatively evaluated by means of attenuated total reflection infrared (ATR-IR) spectroscopy and temperature-programmed desorption (TPD) spectroscopy. The concentration values are correlated to the PS nanoscale morphology. In particular, the influence of porosity, silicon nanocrystallite dimension, and shape on hydrogen concentration values is described. Hydrogen concentrations in fresh, aged, as well as in chemically and thermally treated PS layers are measured. Maximal hydrogen concentration of 66 mmol/g is detected in nanoporous layers with high (>95%) porosity consisting of nanocrystallites with dimensions of about 2 nm. Mass energy density that can be potentially obtained from this amount of hydrogen through a low-temperature fuel cell is estimated to be about 2176 W-h/kg and is found to be comparable with other substances containing hydrogen, such as hydride materials and methanol, which are usually used as hydrogen reservoirs.
  2. Zaitsev, V.N., Kobylinskay, N.G.
    Properties of silicas chemically modified by monodentate amines studied by conductometry
    (2005) Russian Chemical Bulletin, 54 (8), pp. 1842-1846.
    The protonation of aminoalkyl groups covalently bonded on the silica surface was studied by the conductometric titration method. Porous varieties of silica can adsorb HCl from an aqueous solution. Conductometric titration was proposed for the determination of concentrations and constants of protolytic equilibrium of grafted amino groups. During HCl chemisorption the effect of temperature on the electric conductivity of suspensions of the modified silicas was studied. © 2005 Springer Science+Business Media, Inc.
  3. Kovalchuk T. V., Sfihi H., Korchev A. S., Kovalenko A. S., Il’in V. G., Zaitsev V. N., and Fraissard J.
    Synthesis, Structure, and Acidic Properties of MCM-41 Functionalized with Phosphate and Titanium Phosphate Groups,
    J. Phys. Chem. B     2005, 109, 13948-13956.
    Mesoporous molecular sieves Si-MCM-41 (purely siliceous) and Ti-MCM-41 (partly covered with a surface layer of TiO2) were functionalized with phosphate groups by treatment with POCl3 (denoted -MCM-41(P) and Ti-MCM-41(P), respectively). With the use of TEM, X-ray diffraction, and N2 adsorption, it was shown that the initial hexagonal structure, the high specific surface area, and porosity are retained in the functionalized materials but are not as good as in the starting materials. 1H MAS NMR and 31P MAS NMR revealed that the surface of Si-MCM-41(P) consists of silicon phosphate and pyrophosphate species. That of Ti-MCM-41(P) additionally contains titanium dihydro-, hydro-, and pyrophosphate species, the latter being predominant. TPD of adsorbed ammonia for Si-MCM-41(P) and Ti-MCM-41(P) showed that functionalization leads to the creation of moderate and strong acid sites. A combination of mesoporous structure with acidic properties makes the MCM-41 functionalized with phosphate groups promising for use as solid acid catalysts.
  4. Gerda, V.I., Kobylinskaya, N.G., Zajtsev, V.N., Il'in, V.G.
    Synthesis and protolytic properties of the periodically ordered mesoporous organosilicas with MCM-4l-type architectures functionalized by alkylamines
    (2005) Ukrainskij Khimicheskij Zhurnal, 71 (9-10), pp. 112-119.
    Periodically ordered mesoporous organosilicas (POMO) with MCM-4l-type architectures and different contents of alkylamine functional groups on the inner surface of mesopores with fine ordering have been obtained by sol-gel method with cetyltrimethyl-ammonium bromide as a surfactant. Their composition, structurally-sorption characteristics and protolytic properties were determined using XRD, Fourier transform infrared spectroscopy, pH-potentiometric and conductometric titration. It was demonstrated that these materials are characterized by large pore volume and specific surface area compared with chemically modified silica (CMS).
  5. Koval'chuk, T.V., Kostenko, L.S., Zajtsev, V.N.
    Mixed-ligand complexes of La (III) with xylenol orange and silica-grafted complexones
    (2005) Ukrainskij Khimicheskij Zhurnal, 71 (9-10), pp. 68-75.
    The formation of mixed-ligand complexes of La (III) with aqueous solution of xylenol orange (XO) and silica-grafted complexones (SiO2- L, where L - ethylenediaminetetraacetic, iminodiacetic, salicylaminomethylphosphonic and aminodiphosphonic acid) was studied with the use of potentiometry and UV-Vis spectroscopy. Adsorption of XO is pH-independent and proceeds via its coordination to preformed grafted complexes SiO2-L2 · La3+. It results in formation of stable (pH 6-8) mixed-ligand complexes with the structure (SiO2-L2 · La3+)2·XO.
  6. Zajtsev, V.N., Khalaf, V.A., Zajtseva, G.N., Alekseev, S.A.
    Silica modified with poly(ethylene oxide) for phenol preconcentration from aqueous solution
    (2005) Ukrainskij Khimicheskij Zhurnal, 71 (9-10), pp. 59-64.
    New solid phase extractant on the base of silica modified by covalently grafted nonionic surfactant (poly(oxyethylene isooctylphenyl ether) was developed for phenol extraction from water (TX-SiO2). It was stated that its quantitative extraction by the proposed TX-SiO2 is conducted in the form of ion-associate of 4-nitrophenyl azophenolate with cetyltrimethylammonium cation. Thus the distribution coefficients of phenol average 3.4-104 ml/g, and capacity in the Henry area comes to 2.3 mg/g.
  7. Зайцев В.Н., Халаф В.А. (асп.), Зайцева Г.Н., Алексеев С.А. Твердофазний екстрагент для вилучення 2,4,6-тринітрофенолу з водних розчинів // Вісник Київського национального университету імені Тараса Шевченко. Серія «Хімія», 2005, вип.42, с.27-29.
  8. Зайцев В.Н., Костенко Л.С., Янцен В.В.(студ.) Вплив гідрофобізації на кислотні та іонообмінні властивості кремнезему, модифікованого метиламінофосфоновою кислотою // Вісник Київського национального университету імені Тараса Шевченко. Серія «Хімія». - 2005, вип.42, с.15-17.
  9. Зайцев В.Н.,  Рева Т.Д., Зайцева Г.Н. Сорбційно-фотометричне визначення іонів деяких токсичних металів з водних розчинів і біологічних рідин // Вісник Київського национального университету імені Тараса Шевченко. Серія «Хімія».- , 2005, вип.42, с.17-20.
  10. Зайцев В.Н., Халаф В.А.(асп.) Синтез и изучение свойств иммобилизованного на SiO2 2,3,5-трифенилтетразолия для селективного концентрирования пикриновой кислоты. // Вісник Харківського національного університету.-2005, Серія: Хімія.-Вип. 13 (36).-С. 45-49.

Head of the laboratory of chemistry for organo-mineral materials

Department of analytical chemistry Taras Shevchenko National University of Kyiv
60 Vladimirskaya Str., Kiev Ukraine 01601

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tel: +380-97-0980693, e-mail: vnzaitsev@gmail.com, http://anchem.knu.ua/ua/main_ukr.html
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