L. A. Petrov

Synthesis of TiO2-SiO2 xerogels via the hydrolysis of a tetrabutoxytitanium-tetraethoxysilane mixture in aqueous ammonia and hydrochloric acid atmospheres

TiO2-SiO2 xerogels have been synthesized by the hydrolysis of tetrabutoxytitanium-tetraethoxysilane mixtures in a 10% aqueous ammonia vapor and concentrated hydrochloric acid vapor atmospheres under static conditions. The dependence of the physical and chemical properties of the xerogels on the synthetic conditions has been investigated.

TiO2-SiO2 binary xerogels: Synthesis and characterization

Silica/titania binary xerogels were prepared by joint hydrolysis of the ingredients. Gels of various compositions were characterized by 1H NMR spectroscopy, IR spectroscopy, and thermogravimetry. The spectral characteristics of binary systems differ considerably from mere superposition of the spectra of the two constituent compounds and the spectrum of a mechanical mixture. A feasibility was demonstrated for controlling the acid properties of binary oxide gels via varying the component mole ratio.

Synthesis of dispersed silicon, titanium, and zirconium dioxides by pyrolysis of cellulose inorganic composites

The method of the synthesis of dispersed powders of silicon, titanium, and zirconium dioxides was developed, including formation of cellulose inorganic composites by impregnation of pressed granules of powdered cellulose with solutions of tetraethoxysilane and tetrabutoxy zirconium, hydrolysis of the organometallic constituent of the composite, pyrolysis of the cellulose matrix of the composite, and burning of its carbon constituent.

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.

Activated carbon and carbon-oxide composite materials derived from powdered cellulose

Activated carbons were prepared by high-temperature steam activation of carbonized samples of powdered cellulose and composite cellulose-inorganic materials based on it. The dependences of the yield of the material and in its physicochemical characteristics on the initial formula of the composite were found. The sorption activity of the carbons toward hydroquinone was determined, and the model reaction of hydrogen peroxide decomposition in their presence was performed.

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.

EPR study of copper(II) complexes in the matrix of titania gel modified with powder cellulose

The character of the copper(II) distribution over the surface of titania gel modified with powder cellulose has been studied by EPR. Three types of copper(II) compounds have been identified: mononuclear complexes, magnetic associates, and copper(II) compounds that do not give rise to an observable EPR spectrum at the used frequency and temperature. The modification of titania gel has been shown to have an effect on the relative contents of these compounds.

Zirconium dioxide xerogel modified with powdered cellulose

Zirconium dioxide xerogel was synthesized in the presence of powdered cellulose. The samples obtained were studied in a model liquid-phase catalytic process of oxidative dehydrogenation of trimethylhydroquinone with atmospheric oxygen and in decomposition of hydrogen peroxide.

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.