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SAXS and EXAFS were applied to study genesis of polynuclear zirconium hydroxyspecies in pillaring solutions as dependent upon the zirconium concentration, addition of alkaline-earth chlorides and aging. After the montmorillonite clay pillaring, the structure of zirconium nanopillars was characterized by applying X-ray structural analysis, UV-Vis, FTIRS of adsorbed CO and nitrogen adsorption isotherms. Main pillaring species appear to be nanorods comprised of several Zr 4 tetramers. Basic structural features of the tetramers are preserved in zirconia nanoparticles fixed between alumosilicate layers in pillared clays. In calcined samples, those nanoparticles contain only bridging hydroxyls and/or oxygen anions responsible for bonding within pillars and between pillars and clay sheets.

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Approaches to design of zirconia pillared clays via control of the properties of pillaring species in solutions were elaborated. Structural features of pillars and Pt + Cu active components fixed at these nanoparticles were shown to determine catalytic properties of pillared clays in NO x selective reduction by hydrocarbons in the oxygen excess.KEY WORDS: zirconia pillared clay; synthesis; structure of zirconia nanoparticles and texture of clays; copper and Pt-loaded catalysts; reducibility and adsorption properties; catalysis of NO x HC SCR; performance and reaction mechanism

Transformation of surface nitrates under CI-I4 (CH4 + 02) was found to ensure steady-state activity of Co-ZSM-5 in the selective catalytic reduction of nitrogen oxides by methane (CI-I4-SCR). For Cu-ZSM-5, such species are mainly converted into NO. Kelaxation of the coordination sphere due to oxygen and NO adsorption, stability of C,N-containing intermediates and activation routes of hydrocarbons (methane, propane) were analyzed as factors determining catalytic properties of Cu and Co cations.