V. G. Il'in

“From Heteronuclear Complex to Composite Oxide” Approach in the Synthesis of Nanosized Ferrites MIIFeIII2O4 (M = Mn, Co, Ni) with Spinel Structure and Their Catalytic Properties

A study was carried out on the preparation of ferrites MIIFe2O4 (MII = Mn, Co, Ni) by the thermal decomposition of the corresponding μ3-oxoacetates [Fe2MIIO(CH3COO)6(H2O)3]·2H2O. Nanocrystallites of MIIFe2O4 were formed under mild conditions at 300-400 °C in this reaction. An increase in the temperature leads to an increase in particle size. Nickel ferrite showed high catalytic activity in the reduction of nitrogen oxides (NOx) by hydrocarbons.

Deep Oxidation of Methane over Nano-Sized Ferrites with Spinel Structures

Ferrites with spinel structures as catalysts for the deep oxidation of methane have been studied by X-ray phase analysis and temperature programmed reduction. The most active catalysts are the nano-sized ferrites of cobalt and nickel, prepared by the decomposition of polynuclear complexes, with Al2O3 as carrier and with addition of a surface active agent to increase the thermal stability of the catalysts. At low temperatures (up to 450 °C), the effect of the size factor appears with the increase in specific catalytic activity of cobalt and nickel ferrites with decreasing of their particles. A correlation of the catalytic activity with the quantity and mobility (reactivity) of oxygen in the ferrites has been established.

Interrelationship of Structural-Adsorption Characteristics of Titanium Dioxide and Its Photocatalytic Activity in the Gas-Phase Oxidation of Acetone and Ethanol

X-ray phase analysis and adsorption techniques were used to study the effect of heat treatment of starting amorphous titanium dioxide on its structural-adsorption characteristics, which determine the photocatalytic activity in the gas-phase oxidation of acetone and ethanol. In addition to the specific photocatalytic activity of the samples due to the amount of the active anatase TiO2 modification, the adsorption capacity of the photocatalysts, which is a function of the specific surface and pore adsorption volume, affects the rate of the reactions studied.

Effect of Metal Inclusions on the Porous Structure and Photocatalytic Activity of Titanium Dioxide

A study was carried out on the effect of the inclusion of a series of transition metals (V, Cr, Mn, Fe, Ni, Cu, Zr, Mo) and also Al, Si, Zn, and Sn into titanium dioxide on its porous structure, anatase formation, and photocatalytic activity in the generation of molecular hydrogen from aqueous ethanol. An increase in the content of these metals leads to a decrease in photocatalytic activity, while an increase in the anatase content in titanium dioxide leads to an increase in such activity.

FEATURES OF FUNCTIONALIZATION OF MCM-41 SILICA MESOPOROUS MOLECULAR SIEVES DURING THEIR TEMPLATE SYNTHESIS

We have shown that functionalization of MCM-41 mesoporous molecular sieves during their template synthesis using the effect of solubilization of organic hydrophobic co-condensing compounds makes it possible to obtain highly ordered mesoporous molecular sieves, with concentrations of vinyl or allyl groups covalently bonded to the surface of the silica matrix of about 3.5 mmol/g, which after sulfonation have acidic properties and exhibit catalytic activity in the process of ethyl tert-butyl ether synthesis.

Mesoporous Titanium-containing Silicas. Synthesis and geometrical characteristics

Mesoporous titanium-containing silicas with TiO2 contents from 1 up to 70 mol% were prepared. The obtained samples have been characterized by the powder X-ray diffraction data, the diffuse reflectance infrared Fourier transform method, and nitrogen adsorption at 77 K. Specific surface area, total pore volume, distribution pore volume on pore sizes were determined from nitrogen adsorption isotherm for synthesized titanosilicas.

Effect of Isomorphic Incorporation of Titanium on the Structure and Absorption Properties of VPI-8 Zeolites

We have synthesized titanium silicate analogs of VPI-8 zeolite with a broad range of ratios of Si and Ti atoms. We have shown that introduction of titanium into the zeolite lattice is accompanied by an increase in the unit cell parameter from 13.05 Å to 14.85 Å, and also an increase in the sorption capacity and a decrease in the characteristic methanol adsorption energy. X-ray phase analysis, IR and UV spectroscopy have confirmed the isomorphic incorporation of Ti in a tetrahedral environment into the structure of VPI-8 zeolite, up to Ti/(Si+Ti) = 0.05.

Effect of Phosphorylation of Si-MCM-41 and Ti-Si-MCM-41 Mesoporous Molecular Sieves on Their Structure-Adsorption and Acid Properties

Transmission electron microscopy, X-ray diffraction, nitrogen and argon adsorption, thermal analysis, thermoprogrammed ammonia desorption, and 1H MAS NMR spectroscopy were used to show that phosphorylation by POCl3 yields MCM-41 silica gel and Ti-MCM-41 titanium-silica gel mesoporous molecular sieves with about 1.1 mmol/g acid sites consisting largely of hydroxyl group protons of supported phosphoric acid. These materials display catalytic activity in the esterification of acetic acid by ethanol.

Characteristics of Template Formation in Silica in Acidic Media

Characteristics of template formation in silica at pH < 0.1 in the presence of a surface active substance (cetyltrimethylammonium bromide or chloride) have been investigated. Depending on the acidity of the reaction medium and some other factors, the synthesis of spontaneously growing particles of templated silica at interfacial surfaces led to the formation of fibers, spirals, spheres, and other forms, most of which appeared as hexagonally ordered bodies of revolution. It is possible to detemplate these forms of silica and to transform them to mesoporous molecular sieves without destroying their structures.

Effect of Introduction of Aluminum on the Structure and Adsorption Properties of Zeolites of VPI-8 Type

Silicates and aluminosilicate zeolites of the VPI-8 type with wide content range of Si and Al atoms have been synthesized. Introduction of aluminum into the zeolite lattice is accompanied by transition from the cubic to the orthorhombic system while retaining the original architecture of the skeleton, but there is also an increase in the sorption volume and the characteristic adsorption energies of methanol and hexane.