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Mikhalenko Irina Ivanovna, Speaker at Speaker for Catalysis Conference- Mikhalenko Irina Ivanovna
RUDN University, Russian Federation
Title : Zirconium containing ionic materials as catalysts for C3, C4 alcohols conversions

Abstract:

Zirconium containing ternary phosphates Na(Cs)1-2xMxZr2(PO4)3 (NASICON-family) and ternary oxides (vismuth vanadates  Bi4V2–2xZr2xO11–δ of perovskites family) in investigated series of compositions are studied for the vapor-phase selective dehydration and dehydrogenation of isobutanol and isopropanol in the temperature range 200-400 0C. These groups of catalysts represent the solid electrolytes (SE) with cationic and anionic conductivity respectively. The cations M(+2) = Co, Ni, Cu partially substitute the conducting ions Na+ or Cs+. For SE-catalysts characterization the methods XRD, XPS, IR, UVS, SEM, TEM, acidity/basicity surface titration were used. The results demonstrate the correspondence of NASICON frame structures for all of complex phosphates obtained, changes in surface composition vs bulk, different acid/basic sites in M presence and coordination of adsorbed alcohol molecule with hetero-linkages active site V-O-Zr in BIZRVOX. It is found the highest activity for a highly conductive γ-phase of BIZRVOX with selectivity 85–100% for isobutanal formation. The observed step-wise Arrhenius dependences for dehydrogenation reaction are related to changes in the conducting properties of the catalyst. The apparent activation energy decreases linear with phase transformation when Zr content increases. It is found that Cs-Zr-phosphates catalysts prepared by sol-gel procedure showed high selectivity in isobutene formation. But the nature of ion-dopant M as active site is very important too. We found the linear correlation between activation energy (Ea) for isopropanol dehydrogenation reaction (model reaction) and ionic radius of substituting ions M=Ni,Co,Cu in Na-Zr-phosphates prepared by solid phase synthesis. When temperature rises, the change in position M in conductive channel occurs and Ea value of alcohol dehydrogenation reaction diminishes.  So, there are many examples confirming the relationship between conductive and catalytic properties of ionic’s materials.

Biography:

Mikhalenko Irina I. graduated from Peoples Friendship University in 1974, PhD thesis defended in 1978 and a degree of Dr.Sci. in 1997 year. Research interests are adsorption and catalytic chemistry (reactions in vapor and gas phases, electro catalysis, photo catalysis).  Led by I. Mikhalenko 9 graduate students, including 4 foreigners, have succeeded in PhD degree. At the Department of Physical and Colloidal chemistry I. Mikhalenko employs more than 40 years, has more than 200 publications, reads lectures in Physical chemistry, Colloidal chemistry, Nanochemistry, Thermodynamics of Nonequilibrium processes. Physico-Chemistry of surfaces and Chemisorption.

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