O. K. Lebedeva

Effect of the conditions of anodizing on the morphology of nanotitania

The effect the current density, treatment time, surface pretreatment, and electrolyte composition have on the morphology of titania obtained via electrochemical treatment in such ionic liquids (ILs) as 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTf2] and 1-butyl-3-methylimidazolium chloride [BMIM]Cl is studied. The anodic formation of titania nanostructures in the form of nanotubes or nanorods is found to occur in times of up to 100 s. The role of water in the formation of these titania nanostructures is shown. Pretreatment has no effect on the morphology of the formed oxide. The formation of products that are poorly soluble in ILs (e.g., hydrated oxides) results in the emergence of a layer partially covering the open parts of nanotubes, preventing their further growth.

Chemical model for dioxin destruction in aqueous medium: Electrocatalytic oxidation of dioxin-like substance simulating natural pollutant

Chemical model for destruction of dioxin in aqueous phase was suggested. Eosin being similar to dioxins in structure was chosen as a model substance. Eosin seemed to undergo destruction in electrocatalytic systems. For the first time, the adsorption of dioxin-like pollutant, eosin, was detected on platinum electrode at higher potentials than those of oxygen evolution. The kinetics of electrocatalytic oxidation was studied. A total oxidation of substrate to mineral products (carbonates, bromates) occurred over platinized-platinum catalyst. The scheme for electrocatalytic destruction of eosin was discussed. The similar behavior of dioxin in electrocatalytic systems was considered on the basis of the structural similarity and kinetic relationship in eosin and dioxin oxidation.

Synthesis of Nanotitania on the Surface of Titanium Metal in Ionic Liquids: Role of Water Additions

The anodic oxidation of a titanium metal electrode in two ionic liquids was studied of amorphous titania nanostructures were obtained. The nanostructures are formed only in the case where a hydrophilic ionic liquid (1-butyl-3-methylimidazolium chloride) with addition of some water is used as the electrolyte. The role of water is to provide a sort of construction material (source of oxygen) for titania nanostructures. In the hydrophobic ionic liquid (1-butyl-3-methylimidazolium), the thickness of the anodic oxide increases and no nanostructures are formed.

Formation of a regular cellular structure on the surface of Zr67Ni30Si3 alloy at electrochemical polishing in ionic liquids

The surfaces of the alloy based on Zr2Ni doped by silicon (3 at.%) in the amorphous and crystalline states and of the Zr and Ni foils were electrochemically modified for the first time. The modification was carried out in the ionic liquid in the galvanostatic regime. The much more uniform distribution of the nanosized fragments can be obtained and stability of their geometric shapes can be retained in the absence of intergrain boundaries and texture in the amorphous materials.

Separation of copper and bichromate ions by complex methods

Separation of Cu2+ and Cr2O72− has been studied by electrodialysis combined with preliminary adsorption on bentonite. The influence of concentration, pH, and electric current on the degree of desalination has been studied. The optimum conditions for almost complete separation of the ions studied have been found. Real galvanic sewage has been examined by this method.

Erratum to: “Effect of the Conditions of Anodizing on the Morphology of Nanotitania”

The list of authors and their affiliations should read:N. V. Roota, b, D. Yu. Kultina, L. M. Kustova, b, I. K. Kudryavtseva, and O. K. Lebedevaa,*aDepartment of Chemistry, Moscow State University, Moscow, 119991 RussiabN.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Russia*e-mail: lebedeva@general.chem.msu.ru

Formation of Nanostructures on the Nickel Metal Surface in Ionic Liquid under Anodizing

The formation of nanostructures in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide on the surface of a nickel electrode during anodizing was studied. Hexagonal ordered surface nanostructures were found to form in a narrow range of current densities. The form of the potential transients of the nickel electrode corresponded to the morphology of the nickel surface obtained which was studied by electron microscopy. No other types of nanostructures were found under the electrosynthesis conditions under study.

Electrochemical modification of steel by platinum nanoparticles

The aim of this study was to synthesize low-concentration catalysts with a highly developed surface based on nanodispersed platinum deposited onto the steel surface electrochemically modified with the use of an ionic liquid. Sintered fibers of austenitic steel without pretreatment (steel 1) and etched with hydrochloric acid to remove surface oxides (steel 2) were used as substrates. 1-Butyl-4-methylimidazolium acetate [BMIM][Ac] ionic liquid was used. Variation of the current intensity and anodic treatment time leads to the formation of different structures at the steel surface. For steel 2, optimal conditions leading to self-organization, namely, formation of hexagonal structures, have been selected. It has been demonstrated that formation of nanostructures at the steel surface can occur without the participation of fluoride ions. Low-concentration (Pt/steel 2) catalysts with a uniform distribution of platinum nanoparticles over the surface were prepared via galvanostatic deposition from an aqueous solution of H2PtCl6.

Electrocatalytic Oxidation of 2,4,5,7-Tetrabromofluorescein and 2,7-Dichlorofluorescein by Oxygen Adsorbed on Platinum

The development of new catalytic systems based on environmentally safe components is of theoretical and practical importance because of increasing environmental contamination. Promising systems make it possible to decompose ecotoxicants to nontoxic products, which can be achieved by electrocatalytic oxidation with the use of platinum electrodes.