Oxygen Reactions at the Interface of Nonstoichiometric Fluorides LaF3 and CeF3 with Chemically Modified Electrodes

The oxygen reaction at the interface LaF₃(CeF₃)|electrode,O₂(g) is studied in air on Pt and C electrodes and electrodes modified by supported oxides of Co, Sr, and/or La on C, Si, or Pt substrates. The experimental methods used are voltammetry with a linear potential change and stripping voltammetry and cyclic voltammetry. The voltammetric response is dependent on the nature of solid electrolyte and electrode, the balance between the substrate and active agent, and on the conditions of thermal treatment of electrodes. Mobile oxygen forms are discovered at interfaces CeF₃|C (Co _x O _y ), ₂ ([C] : [Co] = 1 : 10, 1 : 20); CeF₃|C (Co _x O _y ), ₂([C] : [Co] = 1 : 10); and CeF₃|Pt (Co _x O _y ), O₂([Pt] : [Co] = 1 : 40). The peak current I _pa in the anodic curves increases with extending the limit of cathodic potential scan E _rc. The peak current I _pc in the cathodic curves increases with extending the limit of anodic potential scan E _ra.     

Synthesis and electrophysical characteristics of VO2-based nanostructures with a complicated architecture on a silicon surface

Nanofilms of complicated architecture based on VO₂ and containing chromium were synthesized by the molecular layering method. The study of electrophysical characteristics of vanadium dioxide nanocrystallites and of VO₂-containing chromium has shown that semiconductor-metal phase transitions appear in the ranges of 130–160 and 100–110 K, respectively. The introduction of a transition-element ion in the nanostructures based on VO₂ affects the phase transition characteristics.     

Electronic Structure of SO3H Functional Groups and Proton Mobility in Nafion and Aquivion Ionomer Membranes

Russian Journal of General Chemistry - The electronic structure of SO3H functional groups in Nafion and Aquivion monomers was calculated. The effect of charge states of the functional group atoms...     

Proton conductivity of composites based on Nafion and silica matrices with a chemically modified surface

The surface of aerosilogel and macroporous and microporous glasses was modified with aromatic sulfo groups (≡Si(CH₂)₂-C₆H₄-SO₃H) by the chemical assembly method. Composite solid electrolytes containing Nafion were prepared from the silica matrices with a chemically modified surface. The proton conductivity of the materials was studied by impedance spectroscopy. Composite materials based on Nafion and aerosilogel matrices and macroporous glasses with grafted ≡Si(CH₂)₂-C₆H₄-SO₃H groups showed the highest proton conductivity.     

Synthesis of composite solid electrolytes based on polyacrylic acid via radical polymerization initiated from silica surface

A procedure has been developed for the synthesis of silica-supported polymerization initiators, which includes chemisorption of (3-aminopropyl)triethoxysilane, hydrolysis of the alkoxy groups, and chemisorption of 4,4′-azobis(4-cyanopentanoic acid). It has been found that the reaction of 4,4′-azobis(4-cyanopentanoic acid) with immobilized amino groups in the presence of N,N′-dicyclohexylcarbodiimide involves only one functional group in the former. The effect of the solid support porosity on the composition of organosilica obtained by surface-initiated radical polymerization of acrylic acid has been studied. The best yield of grafted polyacrylic acid is obtained on aerosilogel with large mesopores in combinations with developed surface. The dependence of the impedance of polyacrylic acid-modified aerosilogel on the relative air humidity has been studied, and the possibility of using this material in humidity sensors has been shown.     

Features of the electronic structure of cerium-based systems

Ce-based systems were studied by means of x-ray photoelectron spectroscopy. The density of states was calculated by the TB-LMTO-ASA and APW+LO band methods. A correlation was found between 4f level localization and x-ray photoelectron spectra with characteristics of the heavy fermion state. It was shown that a high value of interatomic interaction is characteristic of Ce-based systems with heavy fermions under normal conditions.     

Synthesis of Bi-O- and Bi-V-O-containing Nanolayers by Ionic Deposition

A possibility of preparing Bi₂O₃ and BiVO₄ nanolayers by ionic deposition on the silica surface was shown for the first time. The influence of the concentration and pH of reactant solutions and of the number of ionic deposition cycles on the kinetics of the nanolayer growth was studied. The conditions were determined for the formation of a nanolayer by a reaction in a layer of ions sorbed on the surface. The thickness of the synthesized layers was determined by ellipsometry. The layer compositions were studied by X-ray spectral microanalysis, X-ray photoelectron spectroscopy, and UV and IR Fourier transform spectroscopy. The structure of the layers was studied by powder X-ray diffraction.