Alexander V. Gorokhovsky

Resonant scattering and absorption in the titanate-based nanoplatelet dispersions in near ultraviolet region.

Extinction enhancement and nonlinear near-resonant absorption of potassium polytitanate nanoplatelets were experimentally studied in the near-UV region. Phenomenological models such as the one-oscillator Lorentz model for dielectric function and the two-level model with the depleted ground state were used to interpret the experimental data. The introduced model parameters demonstrate the adequately high sensitivity to variations in nanoplatelet morphology and chemical environment.

Data on energy-band-gap characteristics of composite nanoparticles obtained by modification of the amorphous potassium polytitanate in aqueous solutions of transition metal salts

Here we present the data on the energy-band-gap characteristics of composite nanoparticles produced by modification of the amorphous potassium polytitanate in aqueous solutions of different transition metal salts. Band gap characteristics are investigated using diffuse reflection spectra of the obtained powders. Calculated logarithmic derivative quantity of the Kubelka–Munk function reveals a presence of local maxima in the regions 0.5–1.5 eV and 1.6–3.0 eV which correspond to band gap values of the investigated materials. The values might be related to the constituents of the composite nanoparticles and intermediate products of their chemical interaction.

The room-temperature chemiresistive properties of potassium titanate whiskers versus organic vapors

The development of portable gas-sensing units implies a special care of their power efficiency, which is often approached by operation at room temperature. This issue primarily appeals to a choice of suitable materials whose functional properties are sensitive toward gas vapors at these conditions. While the gas sensitivity is nowadays advanced by employing the materials at nano-dimensional domain, the room temperature operation might be targeted via the application of layered solid-state electrolytes, like titanates. Here, we report gas-sensitive properties of potassium titanate whiskers, which are placed over a multielectrode chip by drop casting from suspension to yield a matrix mono-layer of varied density. The material synthesis conditions are straightforward both to get stable single-crystalline quasi-one-dimensional whiskers with a great extent of potassium replacement and to favor the increase of specific surface area of the structures. The whisker layer is found to be sensitive towards volatile organic compounds (ethanol, isopropanol, acetone) in the mixture with air at room temperature. The vapor identification is obtained via processing the vector signal generated by sensor array of the multielectrode chip with the help of pattern recognition algorithms.

Effect of Nanosized Potassium Polytitanate on the Properties of Proton-Conducting Composite Based on Phosphotungstic Acid and Polyvinyl Alcohol

The ionic and electronic conductivity of composite materials based on phosphotungstic acid and polyvinyl alcohol was determined in relation to the concentration of potassium polytitanate (PPT) additive. It was shown that the addition of PPT nanoparticles significantly reduces both the hardening time of the composite material and its electronic conductivity while maintaining high ionic conductivity.

A new gas-analytical device concept via implementation of impedance spectroscopy

Here we discuss the concept of new gas-analytical device based on a.c. driven chemiresistive semiconducting layer. We test the approach utilizing quasi-amorphous potassium polytitanates, K2O·nTiO2·mH2O, which are characterized by high specific surface. In this work, we placed the polytitanate layer over a set of electrodes at the multielectroded chip and measured its impedance under exposure to various gas mixtures. The obtained data allow one to make an equivalent circuit for these structures where the combination of each active/reactive component can be used for selective gas identification.

Photodegradation of Methylene Blue by the Action of Solar Light in the Presence of Potassium Polytitanate Doped with Silicon Oxide

The effect of doping with silicon oxide on the adsorption and photocatalytic characteristics of layered particles of quasiamorphous potassium polytitanate under the influence of radiation simulating sunlight was investigated. It was shown that the increase of photoactivity during the decomposition of methylene blue is due to decrease in the band gap of the doped potassium polytitanate particles.