Electrodeposition of Ni–Fe alloy from a choline chloride-containing ionic liquid

Journal of Solid State Electrochemistry - The electrochemical deposition of a nickel–iron alloy from a plating solution based on a deep eutectic solvent (a eutectic mixture of ethylene glycol...     

Nature of the silver precipitation obtained by cementation from thiosulphate solutions

The morphology and composition of the deposits formed on the surface of magnesium disk during cementation from thiosulphate solutions (0.0025–0.1M) [Ag(S₂O₃)₂]³⁻ + 0.5M S₂O₃ ²⁻ have been studied. A porous deposit with low adhesion is formed on the surface of the magnesium metal substrate. Within a wide range of [Ag(S₂O₃)₂]³⁻ ion concentrations, sulfur as well as silver are constituents of the deposit at the initial stages of cementation and at the end of the reaction. This is attributed to the electrochemical behaviour of magnesium in thiosulphate solutions resulting in the exceeding of current limit on cathode for pure silver reduction. Hence, parallel electrochemical reactions take place that are very close in their values to the standard redox potentials of reduction of [Ag(S₂O₃)₂]³⁻ ions to Ag⁰ and S₂O₃2− ions to S²⁻. Sulfur content in the cement deposits increases with the decrease in [Ag(S₂O₃)₂]³⁻ ion concentration and increase in cementation time. This tendency is also observed with the decreasing solution temperature.     

The Theoretical Study of Interaction of Water Chloride Containing Environment Components with CuAl<Subscript>2</Subscript> Intermetallic Surface

DFT method in a cluster approximation has been used to simulate surfaces of intermetallics CuAl₂ as a structural part of aluminum copper alloys AA2XXX. Geometry and electronic structure of clusters at the surfaces (100) and (110) were calculated. Parameters of adsorbate (water molecules and chloride ions) interaction with the surfaces of the metals were calculated in details. It has been shown that water molecules prefer to adsorb at the intermetallic surface by oxygen atoms in atop sites. The influence of corrosive active chloride ions on the intermetallic surface destruction has been studied in the environment of water molecules for an original molecular model. It gave the possibility of the prevailing dissolution of the (110) surface as compared with the (100) surface. It has been shown that the intermetallic phase is a complicated electrochemical system with the regions of different crystallographic orientation and adsorption sites for the system aluminum–copper, which serve as active local cathode–anode regions. The presence of such regions initiates the intermetallic phase fracture.     

Electrolytic Deposition of Hard Chromium Coatings from Electrolyte Based on Deep Eutectic Solvent

Deposition of chromium coatings from an electrolyte based on a deep eutectic solvent (new type of ionic fluids) was studied. The electrolyte used to deposit the coatings contained choline chloride, chromium(III) chloride, and addition of water. It was found that introduction of a certain amount of water makes it possible to raise the electrical conductivity and reduce the viscosity of the electrolyte to values acceptable for its practical application. The manner in which the electrolysis conditions affect the current efficiency for chromium deposition was determined. It was shown that uniform hard chromium coatings with good adhesion to the substrate can be deposited.     

Two‐step chromatography purification of IgGs possessing sialidase activity from human blood serum

Sialation of cell surface is known to be tightly connected with tumorigenicity, invasiveness, metastatic potential and clearance of aged cells, while sialation of immunoglobulin G (IgG) molecules determines their anti‐inflammatory properties. Recently, we have found for the first time IgG‐antibodies possessing sialidase‐like activity (sialylic abzyme) in blood serum of multiple myeloma and systemic lupus erythematosis patients. This abzyme was detected in a pool of IgGs purified by a typical procedure including immunoglobulin's precipitation with ammonium sulfate and following chromatography on protein G–Sepharose column. Here we describe a novel matrix for affinity purification of sialylic abzyme that is based on using bovine submandibular gland mucin conjugated to Sepharose matrix (mucin–Sepharose). This matrix preferentially binds sialidase‐like IgGs from a pool of sialidase‐active fraction of proteins precipitated with 50% ammonium sulfate from blood serum of the systemic lupus erythematosis patients. That allowed us to develop a new scheme of double‐step chromatography purification of sialidase‐like IgGs from human blood serum. Copyright © 2014 John Wiley & Sons, Ltd.     

Computer Simulation of Binary Platinum–Cobalt Nanoclusters Interaction with Oxygen

On the basis of the quantum-chemical method of density functional theory (DFT) in cluster approximation binary nanoclusters of platinum-cobalt are simulated and their interactions with molecular and atomic oxygen are calculated. It was shown that a binary nanocluster Pt₃₇Co₁₈, constructed of platinum atom outer shell, has the lowest adsorption heat for both molecular and atomic oxygen. This may contribute favorably to accelerate oxygen reduction on catalytic electrodes. The results obtained are in good satisfaction with known experimental and theoretical data, indicating the perspectives of the proposed approximation for theoretical search of chemical composition and structure of effective binary nanocatalysts with platinum as cathode materials in low temperature membrane fuel cells.     

Electrochemical synthesis and properties of iron–titanium dioxide composite coatings

Deposition of Fe/TiO₂ composite coatings from a colloidal methanesulfonate electrolyte containing titanium dioxide hydrosol was studied. The TiO₂ content in the composite increases with increasing the dispersed phase content and decreasing the current density. Incorporation of TiO₂ particles into the iron matrix resilts in an increase in the microhardness of the deposit. The electroplated Fe/TiO₂ composite coating was used as a heterogeneous photocatalyst for the decomposition of an organic dye under the action of UV radiation.