A. B. Shishmakov

Synthesis of spherical TiO2-SiO2 granules by joint hydrolysis of tetrabutoxytitanium and tetraethoxysilane, with KU-23 polymeric cation exchanger used as matrix

Joint hydrolysis of tetrabutoxytitanium and tetraethoxysilane in a desiccator in the presence of water vapor was used to synthesize spherical granules of a TiO2-SiO2 binary xerogel with a KU-23 polymeric cation exchanger used as a matrix. Specific structural features of the resulting new form of the catalytic system were revealed. It was shown that the catalytic activity of titanium contained in the Ti-O-Si mixed amorphous phase substantially exceeds that of TiO2 in the anatase phase.

Synthesis of Cu(II)-containing TiO2-SiO2 binary xerogels by hydrolysis of a mixture of tetrabutoxytitanium, tetraethoxysilane, and copper(II) chloride in a water-ammonia atmosphere

A Cu(II)-containing binary xerogel TiO2-SiO2 was synthesized by joint hydrolysis of tetrabutoxytitanium, teraethoxysilane and copper(II) chloride dissolved in their mixture. The synthesis was performed in a vapor of 10% aqueous ammonia under static conditions. EPR spectroscopy was used to examine the state of Cu(II) in the xerogel matrix. Data on specific features of the behavior of saccharose within xerogel pores under heating were obtained. The catalytic activity of the xerogel was tested by the kinetic method on model reactions of hydrogen peroxide decomposition and oxidative dehydrogenation of trimethylhydroquinone.

Synthesis of porous zirconium and titanium dioxides by hydrolysis of tetrabutoxyzirconium (tetrabutoxytitanium) with atmospheric moisture in the absence of acid-base catalysts with the use of cellulose and activated charcoal as matrices

Synthesis of porous zirconium and titanium dioxides was accomplished by a procedure that includes impregnation of cellulose and activated charcoal matrices with tetrabutoxyzirconium (tetrabutoxytitanium) solutions, hydrolysis of the precursors with atmospheric moisture at 25°C, burning the matrix, and incineration of xerogels at 850°C. Relationship between precursor solution concentration at impregnation stage, matrix type, and physicochemical properties of prepared materials was established.

Synthesis of TiO2-SiO2 and TiO2-SiO2-Cu(II) xerogels by cohydrolysis of precursors in the absence of a solvent and redox catalysts

Cohydrolysis of tetrabutoxytitanium and tetraethoxysilane in a desiccator in the presence of water vapor produced a TiO2-SiO2 binary xerogel and its Cu(II)-containing analog. The hydrolysis was performed without using either a solvent, or redox catalysts. The effect of the synthesis conditions on the physicochemical properties of the obtained material was studied.

Synthesis of double oxides TiO2-SiO2 with low titanium content by hydrolysis of tetrabutoxytitanium-tetraethoxysilane mixture in an atmosphere of water vapor and ammonia

A series of TiO2-SiO2 binary xerogels with the titanium content lower than 7 mol % were prepared by joint hydrolysis of tetrabutoxytitanium and tetraethoxysilane in a desiccator in the atmosphere of vapor over 5% aqueous NH3 solution under static conditions. The physicochemical properties of the material were examined by IR spectroscopy and by the kinetic method with hydrogen peroxide decomposition as model reaction.

Effect of the surface charge on the complexing and catalytic properties of Cu2+-containing composite materials based on zirconia and powdered cellulose

Composite materials (CMs) based on zirconia xerogels and powdered cellulose (PC) were synthesized. The effect of the CM surface charge on their complexing properties with respect to Cu2+ ions and on the catalytic activity of the samples in model reactions of the decomposition of H2O2 and the oxidative dehydrogenation of trimethylhydroquinone with atmospheric oxygen was analyzed. It was experimentally proved that the use of PC for the synthesis of ZrO2-based CMs, as in the case of previously studied CMs based on SiO2 and TiO2, leads to an increase in the specific surface area Ssp and a decrease in the negative electric potential of their surface. The surface charge, sorption method, and the composition of the buffer solution used for sorption have a significant effect on the copper(II) content in the CM phase, the distribution pattern, and the composition of the sorbed copper(II) compounds and on the catalytic activity of the synthesized Cu2+-containing CMs.

Synthesis of SiO2-TiO2 binary composites with cellulose as the substrate

A procedure for the synthesis of the SiO2-TiO2 binary material was developed. The procedure includes the formation of the silica matrix by impregnating cellulose plates with tetraethoxysilane followed by hydrolysis of the organometallic compound and burning-out of the cellulose constituent; activation of silica with HF; and deposition of titanium dioxide on the surface of the silica matrix by impregnating it with a solution of tetrabutoxytitanium, which is hydrolyzed in water-ammonia atmosphere. The physicochemical properties of the obtained material were studied.

Structure and Catalytic Properties of a Cu2+-Containing Hydrogel of Zirconium Dioxide

The distribution of Cu2+ ions in ZrO2 and sulfated ZrO2 hydrogel phases was studied by EPR spectroscopy and voltammetry. The formation of the following three types of copper structures was observed: mononuclear Cu2+ complexes (A), magnetic associates (B), and Cu2+ compounds (C) that gave no EPR signals under the conditions used in the spectroscopic measurements. The specific catalytic activity of various Cu2+ compounds in the liquid-phase reaction of 2,3,5-trimethyl-1,4-hydroquinone oxidation was determined. The copper complexes C were found to exhibit the highest catalytic activity.

Synthesis of TiO2–ZrO2 binary oxides by hydrolysis of tetrabutoxytitanium and tetrabutoxyzirconium mixtures under water–ammonia atmosphere

TiO2–ZrO2 binary oxides were prepared by joint hydrolysis of tetrabutoxytitanium (TBT) and tetrabutoxyzirconium (TBZ) mixtures under an atmosphere of H2O vapor and 10% aqueous NH3 in the batch mode. The physical and chemical properties of the thus-prepared samples were studied as dependent on the synthesis parameters.

Synthesis of TiO2 and TiO2—SiO2 xerogels by hydrolysis of tetrabutoxytitanium and tetraethoxysilane in acetic acid atmosphere

The TiO2 and TiO2—SiO2 xerogels were prepared by hydrolyzing tetrabutoxytitanium or its mixture with tetraethoxysilane. The synthesis was conducted in an acetic acid—water atmosphere under stationary conditions followed by calcinations. The final TiO2 and TiO2—SiO2 xerogels represented 3D globular pore structure with a narrow globule size distribution. At hydrolysis of terabutoxytitanium, acetic acid vapors favored formation of TiO2 xerogel with a higher surface area compared to the material produced without acidic catalyst.