M.S. Vasilyeva

WOx, SiO2, TiO2/Ti composites, fabricated by means of plasma electrolytic oxidation, as catalysts of ethanol dehydration into ethylene

WO3, SiO2, TiO2/Ti composites are fabricated and studied by means of X-ray diffraction analysis and X-ray photoelectron and IR spectroscopy. It is established that the surface of an oxide coating contains up to 2% of tungsten in the composition of WO3, SiO2, and TiO2, along with carbon compounds. Data on the catalytic activity of SiO2, TiO2/Ti and WO3, SiO2, TiO2/Ti composites in ethanol dehydration are obtained. In the case of WO3, SiO2, TiO2/Ti composites, the degree of conversion and the selectivity of ethanol transformation into ethylene at 480°C reaches 97%.

Silicate anodic coatings on aluminum containing oxides of cobalt and/or copper and/or cerium and their activity in CO oxidation

Coatings on aluminum alloy containing one or several crystalline oxides of cobalt, copper, and cerium deposited in different sequences have been obtained by a combination of methods of plasma electrolytic oxidation and impregnation followed by annealing. It has been established that the composition of surface layers and the catalytic activity of composites depend on the sequence of deposition of active components on the substrate. Cu2+, Cu+, Co3+, Ce4+, and Ce3+ are present in the surface and subsurface layers. All the studied composites are characterized by catalytic activity in the reaction of oxidation of CO into CO2. Of the studied composites, the following are most active: CexOy/CuO/SiO2 + Al2O3/Al, CexOy/Co3O4/CuO/SiO2 + Al2O3/Al, and CexOy/CuO/Co3O4/SiO2 + Al2O3/Al.

An effect of heat processing on catalytic activity of a system MnO x ,SiO2/TiO2/Ti

An effect of annealing in air at temperatures 250, 350, 500, and 700°C on composition, surface structure, and catalytic activity in CO oxidation of a system MnOx,SiO2/TiO2/Ti formed by combining methods of plasma electrolytic oxidation and impregnation was examined.

Deposition of cobalt-containing films on titanium by plasma electrolytic oxidation

The possibility of forming Co-containing coatings on titanium by plasma electrolytic oxidation and by a combination of oxidation and impregnation methods using an aqueous solution of sodium silicate as the base electrolyte was examined. Comparative analysis of the composition and structure of the systems obtained and of their activity in oxidation of CO to CO2 was performed.

Photocatalytic properties of Zn- and Cd-containing oxide layers on titanium formed by plasma electrolytic oxidation

Element and phase compositions, surface morphology, and photocatalytic activity of oxide coatings on titanium formed by the method of plasma electrolytic oxidation in sulfate and phosphate electrolytes with and without addition of cadmium and zinc salts have been investigated. The coatings were studied by means of the X-ray spectral method, X-ray diffraction analysis, and electron microscopy. The photocatalytic activity of oxide layers depends on their element and phase composition and surface morphology. The highest photocatalytic activity in the reaction of degradation of Methylene Blue is demonstrated by titanium oxide coatings doped with cadmium.

Composition, structure, and photocatalytic properties of Fe-containing oxide layers on titanium

The composition, optoelectronic properties, and surface and cross-section morphology of coatings formed by the method of plasma electrolytic oxidation in electrolytes containing sodium phosphate or silicate with or without addition of K3[Fe(CN)6] have been investigated. The coatings were studied by the methods of spectrophotometry, X-ray diffraction analysis, electron microscopy, and X-ray photoelectron spectroscopy. The photocatalytic activity of oxide coatings was studied in the reaction of phenol degradation under ultraviolet irradiation in the presence of hydrogen peroxide. The highest photocatalytic activity in the reaction of phenol degradation in the presence of hydrogen peroxide was manifested by Fe-containing coatings formed in the silicate electrolyte with addition of 8.0 g/L of K3[Fe(CN)6].