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Using the method of niobia electrochemical anodizing via the porous alumina, three types of nanostructures: skittle-, medusa- and goblet-like niobia embryos were formed. Their morphology and formation boundary conditions were investigated. Established up to 37 V embryos are formed like skittles, in the region from 53 to 100 V medusa-like are formed, and above 150 V – goblet-like. To research the optical column-like niobia nanostructure properties inside porous alumina, embryos 53 V like medusa were formed on a glass substrate and re-anodized to a voltage of 230 V not to leave the metallic niobium. Investigations have shown the complete absorbance of the ultraviolet range and the presence of transmittance, reflectance and absorbance in the visible and infrared range with significant oscillations, which indicates the presence of Fabry-Perot interference.

Плотные и мезопористые пленки диоксида титана получены на титановых подложках методами термического окисления, гидролиза полибутилтитаната, нанесения золя диоксида титана, ультразвуковой обработки и анодного окисления и охарактеризованы с помощью сканирующей электронной микроскопии, просвечивающей электронной микроскопии и спектроскопии комбинационного рассеяния света. Электрохимическая активность диоксидтитановых пленок, исходных и модифицированных наночастицами золота, в реакции восстановления кислорода в щелочной среде исследована методом циклической вольтамперометрии. Показано, что эффективность протекания реакции восстановления кислорода на плотных и мезопористых диоксидтитановых пленках определяется их морфологией, структурой, а также степенью упорядоченности пор. Модифицирование пленок диоксида титана наночастицами золота приводит к снижению перенапряжения реакции электровосстановления кислорода. Установлено, что электроды, состоящие из высокоупорядоченных слоев нанотрубок диоксида титана с нанесенными наночастицами золота, демонстрируют существенно большую электрокаталитическую активность в реакции восстановления по сравнению с TiO2/Au-системами на основе плотных пленок и мезопористых пленок с неупорядоченной структурой пор. Свойства электрохимического поведения системы TiO2/Au (нанотрубки/наночастицы) объясняются особенностями транспорта электронов к поверхности электродов и структурой области пространственного заряда в мезопористой пленке оксида.

In the paper, experimental results concerning the dynamics of the counter interaction of high-energy plasma flows in a magnetic field with an induction of up to 2 T are presented and discussed. Plasma flows with velocities (2–4) × 107 cm/s, ion density (2–4) × 1015 cm–3, and energy content of 70–100 kJ were formed by two electrodynamic coaxial accelerators with pulsed gas injection. Nitrogen and neon, as well as their mixtures with deuterium, were used as working gases. A description of the 2MK-200 facility, where the experiments were carried out, and diagnostic equipment are presented. Experimental results obtained in various operating modes of the facility are reported and discussed.

Epoxy based composites filled with RhB-loaded TiO2 containers were prepared. SEM, EDX mapping, and Raman spectroscopy showed a uniform distribution of the TiO2 particles in the polymeric matrix. The sensitivity of the composites to UV irradiation was studied. Efficiency of the composite decolorization was found to depend on the amount of RhB-loaded TiO2 containers incorporated into the coating. Accelerated decomposition of Rhodamine B in the composite under UV irradiation takes place due to photocatalytic activity of the TiO2 particles. The prepared composites can be used as UV-sensor material.

The influence of arsenazo-I additive on electrochemical anodizing of pure aluminum foil in malonic acid was studied. Aluminum dissolution increased with increasing arsenazo-I concentration. The addition of arsenazo-I also led to an increase in the volume expansion factor up to 2.3 due to the incorporation of organic compounds and an increased number of hydroxyl groups in the porous aluminum oxide film. At a current density of 15 mA·cm−2 and an arsenazo-I concentration 3.5 g·L−1, the carbon content in the anodic alumina of 49 at. % was achieved. An increase in the current density and concentration of arsenazo-I caused the formation of an arsenic-containing compound with the formula Na1,5Al2(OH)4,5(AsO4)3·7H2O in the porous aluminum oxide film phase. These film modifications cause a higher number of defects and, thus, increase the ionic conductivity, leading to a reduced electric field in galvanostatic anodizing tests. A self-adjusting growth mechanism, which leads to a higher degree of self-ordering in the arsenazo-free electrolyte, is not operative under the same conditions when arsenazo-I is added. Instead, a dielectric breakdown mechanism was observed, which caused the disordered porous aluminum oxide film structure.

In this work, the degradation of terephthalic acid (TA) by vanadium oxide (VxOy) supported on zinc oxide (ZnO) was evaluated in a photocatalytic ozonation treatment based on two UV-A LEDs distribut...

Niobium and tantalum anodic oxide nanocolumn arrays by porous anodic alumina assisted anodizing were produced and the optical reflectance was studied.

This study evaluates naproxen (NP) degradation efficiency by ozonation using nickel oxide films (NiO(F)NiO(F)) as a catalyst. The NiO films were synthesized by chemical vapor deposition and characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. NP degradation was conducted for 5 min using 10 films of NiO(F) comparing against ozonation using 100 mg/L NiO powder in suspension (NiO(s)NiO(S)) and conventional ozonation (O3-conv). Total organic carbon analysis demonstrated a mineralization degree of 12% with O3O3-conv, 35% with NiONiO as powder and 22% with NiO(F)NiO(F) after 60 min of reaction. The films of NiO(F)NiO(F) were sequentially used 4 times in ozonation demonstrating the stability of the synthesized material, as well as its properties as a catalyst for ozonation. A proposed modeling strategy using robust parametric identification techniques allows the comparison of NP decomposition pseudo-monomolecular reaction rates.

The structure and composition of a zinc‑aluminum layered double hydroxide (Zn2Al LDH) with the intercalated 2-mercaptobenzothiazole corrosion inhibitor (a.k.a. benzo[d]thiazole-2-thiol) are interpreted by means of atomistic molecular dynamics (MD) simulations. The results concerning the proportion of intercalated 2-mercaptobenzothiazole and water species in the Zn2Al LDH interlayer were correlated with experimental X-ray diffraction (XRD) and thermogravimetric analysis (TGA) data of samples obtained at pH 8.5, 10 and 11.5. While the sample synthesized at the lowest pH is almost free of contaminants, the sample obtained at the highest pH is contaminated by a small fraction of a material with intercalated OH−. The comparison of the calculated and XRD interlayer distances suggests that the most stable structure has a ratio of ~4.5 water molecules per intercalated organic species, which is higher than the ratio of ~2 typically reported in the literature. The distribution of molecules in the LDH interlayer consists of a layer of water near the hydroxides, a second layer grown over the first layer, with the 2-mercaptobenzothiazole species adopting conformations with the sulfur of the thioamide group facing the hydroxide/water layers and the 6-member ring oriented towards the middle of the interlayer. Different structural analyses were done to explain the equilibria between the different species in the interlayer space, and their molecular interactions with the LDH metal hydroxide layers.

Encapsulated metal nanostructures were prepared using the powerful pulsed discharge method. Metal nanorods were obtained in porous titania and alumina matrix by direct electrodeposition from 1-ethyl-3-methylimidazolium chloride-based ionic liquids. The deposition process was characterized by cyclic voltammetry. Morphology of the encapsulated structures was studied by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) for morphological and elemental analysis. It was found that the most efficient method for electrodeposition of pure aluminum into titania nanotubes is the potential cycling method, while for deposition of the Al-Ti alloy in alumina pores a pulsed method with three different steps is preferable. Closing the titania nanotubes was found to be possible both with empty and metal-filled pores, whereas in alumina matrix this procedure can be performed only when pores are filled with a conductive material. The obtained results throw light on the mechanism of porous film encapsulation under high-voltage pulses and allow preparing encapsulated nanostructures in the oxide films.

Results are presented from experimental studies of a pulsed source of soft X-ray (SXR) emission with photon energies in the range of 0.4–1 keV and an output energy of 2–10 kJ. SXR pulses with a duration of 10–15 μs were generated in collisions of two plasma flows propagating toward one another in a longitudinal magnetic field. The plasma flows with velocities of (2–4) × 107 cm/s and energy contents of 70–100 kJ were produced by two electrodynamic coaxial accelerators with pulsed gas injection. Nitrogen and neon, as well as their mixtures with deuterium, were used as working gases. The diagnostic equipment is described, and the experimental results obtained under different operating conditions are discussed. In particular, X-ray spectroscopy was used to study the high-temperature plasma produced in a collision of two plasma flows. The observed intensities of spectral lines are compared with the results of detailed kinetic calculations performed in a steady-state approximation. The calculations of the nitrogen and neon kinetics have shown that the electron temperature of a nitrogen plasma can be most conveniently determined from the intensity ratio of the resonance lines of He- and H-like nitrogen ions, while that of a neon plasma, from the intensity ratio between the resonance line of He-like Ne IX ions and the 3p−2s line of Li-like Ne VIII ions. In the experiments with plasma flows containing nitrogen ions, the electron temperature was found to be ≈120 eV, whereas in the experiments with plasma flows containing neon ions, it was 160–170 eV.

We have investigated the influence of the ratio cement:fly-ash and the temperature of mixing water on the properties of aerated concrete mixes and aerated concrete. It was established that the rational cement-fly ash ratio is 1:1; the mixing water temperature is 40 °C. Experimental research confirmed that the introduction of waste from salt processing and metakaolin to the formulation of binding compositions leads to the formation, rather than the metastable hexagonal calcium hydro-aluminates, of the stable compounds in the structure of partitions between pores of the hydrocalumite and hydrocarboaluminate type. That allowed the targeted structure formation of partitions between pores of the non-autoclaved aerated concrete, which improves the density of partitions and the strength of aerated concrete. It is shown that the introduction of polypropylene fibers to composition of aerated concrete does not affect the kinetics of swelling of the aerated concrete array. However, the introduction of polypropylene fibers improves the strength of aerated concrete based on the modified binding composition containing metakaolin by 47 %, the modified binding composition containing carbonate-containing waste ‒ by 32 %. For the aerated concrete of the В1.5–В2 class of strength, at a density within 615‒625 kg/m 3 , the estimated coefficient of thermal conductivity is 0.16 W/(m∙K), which makes it possible to reduce heat losses through external enclosures. Thus, there is reason to assert the possibility of the targeted control over the processes of forming a strong structure of partitions between pores using the modified binding compositions containing supplementary cementitious materials. The application of polypropylene fibers enables the reinforcement of aerated -concrete array, forming a strong structural frame of partitions between pores, and ensuring greater strength of the non-autoclaved aerated concrete.

Three microbial consortia (C2, C4, C5) grown under photoheterotrophic conditions assimilated acetate and butyrate, as individual and mixed substrates. By controlling the culture conditions, it was possible to manipulate the microbial population composition and thus the yield of polyhydroxyalkanoates (PHA) accumulation. Under limited ammonium conditions, pH control, and a sequential two-step process, C2 and C4 produced PHA. C4 showed the highest production of 44% of the cell dry mass (CDM), close to the theoretical value calculated with a stoichiometric balance. Analysis of the confocal microscopy images confirmed the accumulated biopolymer percentages produced by each consortium, and it was in close correlation with microbial distribution and substrate consumption pattern. 1H, 13C, NMR, and MALDI-TOF spectra identified the primary structure of the obtained biopolymers as copolymers of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV). This composition allows for better mechanical properties compared to the PHB homopolymer. Microbial characterization showed a similar microbial population with different proportions for C2 and C4. The highest PHA production in C4 was associated with higher abundances of PHA producers, including Clostridium (29%), Pseudomonas (8%) and Rhodopseudomonas (5%). Both microbial consortia showed that a portion of their microbial populations were able to perform syntrophic reactions (Dysgonomonas and Clostridium).

The article describes use of an Induction furnace with cold crucible as a tool for real-time measurement of a melted material electrical resistivity. The measurement is based on an inverse problem solution of a 2D mathematical model, possibly implementable in a microcontroller or a FPGA in a form of a neural network. The 2D mathematical model results has been provided as a training set for the neural network. At the end, the implementation results are discussed together with uncertainty of measurement, which is done by the neural network implementation itself.

Three FTO-BiVO4 photoelectrodes are fabricated modifying the BiVO4 thickness, and systematically evaluating the influence of FTO substrate on the optical, electrical properties, and photoelectrochemical performance of BiVO4 semiconductor. The catalysts are characterized using two light sources with back-side or front-side irradiations, to investigate the impacts of different energy sources and configuration illumination on the FTO-BiVO4 photoactivity. This analysis reveals the existence of an additional charge transfer resistance increasing with thickness film subjected to front-side illumination, while the resistance remarkably diminishes when this interface is directly irradiated under back-side illumination. The highest photocurrent is achieved with the LED lamp under back-side illumination, condition selected to compare the degradation of 20 mg L−1 ciprofloxacin (CIP) in 0.05 M NaCl through electrocatalysis, photocatalysis, and photoelectrocatalysis using front-side or back-side illuminations. In these evaluations, modified FTO contributes to the photogeneration of reactive chlorine species, whence it cannot be considered as a simple substrate. Back-side illumination presents a higher CIP elimination in comparison with front-irradiation. A schematic energy band diagram relying on Tauc and Mott-Schottky plots, and incorporating FTO as a photoactive semiconductor is established to rationalize the formation of oxidant species in the system. A degradation mechanism is established based on HPLC measurements of the different treatment methods.

Three types of niobia nanostructured films (so-called native, planarized, and column-like) were formed on glass substrates by porous alumina assisted anodizing in a 0.2 M aqueous solution of oxalic acid in a potentiostatic mode at a 53 V and then reanodizing in an electrolyte containing 0.5 M boric acid and 0.05 M sodium tetraborate in a potentiodynamic mode by raising the voltage to 230 V, and chemical post-processing. Anodic behaviors, morphology, and optical properties of the films have been investigated. The interference pattern of native film served as the basis for calculating the effective refractive index which varies within 1.75–1.54 in the wavelength range 190–1100 nm. Refractive index spectral characteristics made it possible to distinguish a number of absorbance bands of the native film. Based on the analysis of literature data, the identified oxide absorbance bands were assigned. The effective refractive index of native film was also calculated using the effective-medium models, and was in the range of 1.63–1.68. The reflectance spectra of all films show peaks in short- and long-wave regions. The presence of these peaks is due to the periodically varying refractive index in the layers of films in two dimensions. FDTD simulation was carried out and the morphology of a potential 2-D photonic crystal with 92% (wavelength 462 nm) reflectance, based on the third type of films, was proposed.

The volumetric growth, composition, and morphology of porous alumina films fabricated by reduced temperature 280 K galvanostatic anodizing of aluminum foil in 0.4, 1.0, and 2.0 M aqueous sulfuric acid with 0.5–10 mA·cm−2 current densities were investigated. It appeared that an increase in the solution concentration from 0.4 to 2 M has no significant effect on the anodizing rate, but leads to an increase in the porous alumina film growth. The volumetric growth coefficient increases from 1.26 to 1.67 with increasing current density from 0.5 to 10 mA·cm−2 and decreases with increasing solution concentration from 0.4 to 2.0 M. In addition, in the anodized samples, metallic aluminum phases are identified, and a tendency towards a decrease in the aluminum content with an increase in solution concentration is observed. Anodizing at 0.5 mA·cm−2 in 2.0 M sulfuric acid leads to formation of a non-typical nanostructured porous alumina film, consisting of ordered hemispheres containing radially diverging pores.

The characteristics (composition of the quenched samples, ingot, and evaporation products) are studied of the melt of the corium–high alumina cement system in a weight ratio of 1: 1. In the quenched samples of the melt and ingot, signs of phase separation in the molten state are found. Below a temperature of 2100°C above the melt, aerosol particles with trimodal size distribution are formed; however, above this temperature, the nature of the granulometry of aerosols is bimodal. Moreover, the formation rate of aerosols increases dramatically. The form of aerosol particles under all the experimental conditions was spherical.

Acompounded mixture of fritted white, bright, glass ceramic, glaze coating for household majolica in the system Na2O–K2O–CaO–B2O3–Al2O3–ZrO2–SiO2 is developed. The structure of the coating is distinguished by homogeneity and uniformity of the distribution of the crystalline formations over the entire volume of the glaze. The physical and chemical properties of the glaze coating (CLTE = (50.2 – 50.5) × 10 –7 K–1, thermal resistance 150°C, whiteness 80 – 82%, brightness 87 – 89%, microhardness 5350 – 5400 MPa) attest an appropriate ratio of the crystalline and glassy phases in the glass ceramic coating formed.

The behavior of a melt of a UO2–ZrO2–SiO2–Fe3O4–CaO–Al2O3 system that is formed in the case of the dilution of corium (a melt of a UO2–ZrO2–Zr system) with sacrificial materials (a mixture of aluminum and iron oxides with Portland cement) has been studied. It has been found that, as a result of the evaporation of oxides, spherical aerosol particles are formed, the sizes of which have a trimodal distribution (1, 5, and 11 μm) and the composition of which depends on the nature of the atmosphere over the melt: 90.8UO2 · 5.2SiO2 · 4.0Fe3O4 in the atmosphere of nitrogen and 68.9U3O8 · 6Al2O3 · 2.5Fe3O4 · 22.5Na2O in air.

Seebeck coefficient values measured for textured polycrystalline Bi films have been compared with numerically computed ones. The proposed computation procedure requires crystallographic texture mapping and values of single-crystalline transport coefficients as input data. The comparison of computed and measured Seebeck coefficients allowed determining the factors affecting films' transport properties except of crystalline texture. Two particular cases are considered: when the film properties are affected only by texture and when they depend on texture and grain size simultaneously.

Changes in the intensity of evaporation and the composition of condensing oxides are experimentally studied upon diluting corium by iron(III) oxide and Portland cement. It is found that the formation rate of aerosols over the melt is reduced upon diluting the corium by the studied sacrificial material by almost an order of magnitude up to 0.5 g/(cm2 s). In the reducing atmosphere, the form of the particles of the aerosols is octahedral and in an oxidizing atmosphere it is spherical.

Thin oxide films were prepared electrochemically on the aluminum surface using the high-voltage discharge and potentiostatic methods in deionized water as an electrolyte. The growth of continuous films occurred only at potentials lower than the breakdown potential. The films obtained by the discharge method are more uniform and can grow to a higher thickness in comparison to those formed by the potentiostatic mode, as demonstrated by electrochemical impedance spectroscopy (EIS), transmission electron microscopy (TEM), and scanning Kelvin probe force microscopy (SKPFM). The data herein obtained can be used as a reference to understand better the properties of the films produced in conventional electrolytes where apart from water other species are present. (C) The Author(s) 2016. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. All rights reserved.

The chemical dissolution&mdash, in 0.1 M solutions of phosphoric, malonic, citric, sulfosalicylic, and tartaric acids and 0.6 M solutions of sulfuric, oxalic, malonic, phosphoric, tartaric, and citric acids&mdash, of aluminum (Al) and its barrier anodic oxide, with thicknesses of 240 and 350 nm, produced during the anodization of Al deposited on a sitall substrate and Al foil, respectively, in a 1% citric acid aqueous solution, was investigated. Signs of chemical dissolution for 0.1 M phosphoric acid solution and 0.6 M concentrations of all the listed solutions were found. It was shown that the dissolution rate and the nature of its change depend on the acid nature, the state of the sample surface, and the classification of the electrolytes according to their degrees of aggressiveness with respect to aluminum.

For a criticality assessment of the fuel debris generated by the Fukushima–Daiichi Nuclear Power Plant accident, knowing the segregation of neutron absorber materials, i.e., Gd, B, and Fe, in the fuel debris is necessary. Although B may mostly evaporate during melting, Fe and Gd are expected to remain in the molten corium. To understand the redistribution behavior of Gd and Fe during the solidification of the molten corium, solidification experiments with simulated corium (containing UO2, ZrO2, FeO, and Gd2O3 with a small amount of simulated fission products such as MoO3, Nd2O3, SrO, and RuO2) were performed using a cold crucible induction heating method. The simulated corium was slowly cooled from 2500 °C and solidified from the bottom to the top of the melt. An elemental analysis of the solidified material showed that the Fe-concentration in the inner region increased up to approximately 3.4 times that in the bottom region. This suggested that FeO might be concentrated in the residual melt and that, consequently, the concentration of Fe increased in the later solidification region. On the contrary, the Gd concentration in the periphery region was found to be approximately 2.0 times higher than that in the inner region, suggesting the segregation of Gd in the early solidified phase and to remain with the residual, UO2-rich phase even after oxidative losses. No significant segregation was observed for the simulated fission products.

Mesoporous ZnO materials have been synthesized through chemical deposition of different precursors from aqueous or water-ethanol solutions followed by their thermal decomposition at 400°C in air. The microstructure and morphology of the precursors and obtained ZnO powders were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and nitrogen adsorption-desorption (BET) methods. The structure of the precursor and physico-chemical properties of final zinc oxide powders were shown to be considerably influenced by the presence of Cl– ions and ethanol in solution. In water-ethanol solutions, Zn5(OH)8Cl2∙H2O or Zn5(OH)8(NO3)2∙(H2O)2 precursors are formed, while ZnO particles are directly deposited from aqueous solution. The photocatalytic activity of the synthesized ZnO materials was evaluated by the decolorization of Rhodamine B (RhB) upon UV irradiation. The ZnO powders have demonstrated high photocatalytic efficiency, enabling decomposition of 81.4-97.4 % RhB within 3 hours. The increased photocatalytic efficiency of ZnO prepared by annealing of Zn5(OH)8Cl2∙H2O precursor or deposited directly from aqueous chloride-containing solutions can be originated from the presence of Cl-containing compounds remaining after thermal treatment of simonkolleite as well as from introduction of Cl-dopant in ZnO.

This article is focused on the calculation of heat flux through a calorimeter wall. The stainless steel calorimeter is considered to be submerged into a molten metal, specifically a molten stainless steel. The main objective of the investigation is to define conditions that should be followed to prevent calorimeter from being melted. Thermal field and cooling medium flow are taken into account in this task. The thermal problem is solved using the heat transfer equation with modified boundary conditions. Heat flux flowing into the cooling medium from the calorimeter wall is solved using criterion equation and dimensionless numbers. The results are discussed taking into account small-scale experiment made without the melting of the calorimeter risk. In the small-scale experiment, copper is used instead stainless steel to produce the calorimeter and alloy Sn63Pb37 is melted.

Galvanostatic formation of nanoporous anodic films on aluminum was performed in 0.6 mol·dm − 3 malonic acid electrolyte over a wide current density range in order to define the relationship between the anodizing behavior, oxide growth, dissolution and volume expansion of the oxide. The volume expansion and aluminum dissolution increase with raising the current density, the latter indicating an increasing potential difference across the electrolyte/barrier-layer interface. The same potential difference promotes dissociation of the acid molecules and incorporation of electrolyte-derived species into the film. The increase of volume expansion occurs in three phases, resulting from the two dissociation steps of malonic acid and from the change in the oxide growth mechanism at higher current densities. Infrared spectroscopy showed an enhanced presence of OH in films formed at higher current densities, indicating that lower coordination of aluminum as well as anion incorporation contributes to volume expansion of the oxide. The current appeared to be 100% ionic in the interval of 5–100 mA·cm − 2 , while being about 10% electronic beyond this range. At higher current densities a self-localizing mechanism concentrates the ionic current to a smaller, spot-like area that moves continuously along the sample consuming steadily the whole metal thickness under the spot and thus forming a porous anodic film of highly self-ordered morphology, without physical imperfections. The volume expansion factor of the oxide becomes independent of the anodization current density under these conditions.

Cadmium sulfide nanoparticle (NP) deposition by the successive ionic layer adsorption and reaction (SILAR) method on the surface of mesoporous ZnO micro-platelets with a large specific surface area (110 ± 10 m2g− 1) results in the formation of ZnO/CdS heterostructures exhibiting a high incident photon-to-current conversion efficiency (Y) not only within the region of CdS fundamental absorption (Ymax = 90%; 0.1 M Na2S + 0.1 M Na2SO3), but also in the sub-band-gap (SBG) range (Ymax = 25%). The onset potentials of SBG photoelectrochemical processes are more positive than the band-gap (BG) onset potential by up to 100 mV. A maximum incident photon-to-current conversion efficiency value for SBG processes is observed at larger amount of deposited CdS in comparison with the case of BG ones. The Urbach energy (EU) of CdS NPs determined from the photocurrent spectra reaches a maximal value on an early deposition stage (EU = 93 mV at SILAR cycle number N = 5), then lowers somewhat (EU = 73 mV at N = 10) and remains steady in the range of N from 20 to 300 (EU = 67 ± 1 mV). High efficiency of the photoelectrochemical SBG processes are interpreted in terms of light scattering in the ZnO/CdS heterostructures.

The results of research on the possibility of using galvanic sludge as components of the raw material composition for the manufacture of furnace tiles are reported and it is shown that the sludge affects the thermophysical characteristics of the articles. The introduction of the sediments of the industrial sewage from the galvanic production at Atlant JSC and Belorussian MetallurgicalWorks JSC in the amount 9% promotes the formation of ceramic structure with a rational ratio of the crystalline, liquid, and gas phases, which decreases the thermal conductivity of the material while preserving the required mechanical strength and heat resistance.

Grain structure and the temperature dependences of resistivity, magnetoresistance, Hall and Seebeck coefficients measured in the range from 4 to 300 K were investigated for polycrystalline bismuth films obtained by the melt spinning (MS) and electrochemical deposition (ECD) methods. Charge-carrier concentration and mobilities were calculated assuming the carrier scattering on acoustic deformation potential as the dominant scattering mechanism, parabolicity of holes dispersion law, implying the Lax model for L-band electrons and neglecting the influence of L-band holes on conductivity. The experimental results and calculations have demonstrated that the electrical properties of the Bi films studied are strongly affected by the grain-boundary density.

Received: 20.10.2017; accepted: 15.11.2017; published: 25.12.2017. The Bi4–xPrxTi3O12 (BPT) solid solutions (x = 0.05, 0.10, 0.15) with small praseodymium content were prepared by solid-state method. Thermal, electric, and dielectric properties of BPT were studied. It was revealed that BPT titanates crystalize in аn orthorhombic structure and exhibit p-type semiconductivity. Dielectric constant of BPT increased, Curie temperature (TC), electrical conductivity and dielectric losses decreased, but lattice parameters and thermo-EMF coefficient remained practically unchanged with the increase of praseodymium content in layered Bi4–xPrxTi3O12. It was determined that activation energy of direct current (DC) electrical conductivity and linear thermal expansion coefficient (LTEC) of BPT changes at ferroelectric (FE) → paraelectric (PE) phase transition. The activation energy and LTEC changed below and above TC from 1.08–1.56 eV to 0.45–0.86 eV and from (9.10–10.80)·10–6 K–1 to (13.12–14.61)·10–6 K–1, respectively. The AC electrical conductivity studies of BPT illustrated short-range order with ionic translations assisted by small-polaron hopping. This work was carried out within the framework of State Program of Scientific Investigations of Belarus Republic «Physical materials science, new materials and technologies » (subprogram «Materials science and technologies of materials», task 1.17).

This work focuses on spectral sensitization of mesoporous TiO 2 films and Nb-doped TiO 2 films with polydisperse PbSe nanoparticles (TiO 2 /PbSe). For this, PbSe was electrochemically deposited from aqueous solution containing Pb 2+ cations and SeO 2 . Chemical amount of electrodeposited PbSe was controlled by deposition time and impacted on the magnitude of sensitized photocurrents. The efficacy of different ions (S n 2− ; I 3 − ; H 2 PO 4 − ; N 2 H 5 + ; SO 3 2− ; SCN − , SeSO 3 2− ) as hole scavengers for TiO 2 /PbSe photoanodes was assessed by dynamics of photocurrent in polarization measurements. Electrolyte of Na 2 SO 3 and Na 2 SeSO 3 is reported as an effective one to attain stable photocurrent. Photoelectrochemical cells with TiO 2 /PbSe photoanodes show solar to electricity conversion efficiency of 0.09%, in spectral region up to 700 nm for undoped TiO 2 . Enhancement of the photoresponse was achieved by different level of Nb doping into mesoporous TiO 2 film. Extension of spectral response up to 800 nm and photocurrent conversion efficiency of 0.24% is observed for TiO 2 /PbSe photoanodes with 2.5 at% Nb-doped TiO 2 . Doping with Nb results in positive shift on electrochemical scale of conduction band of TiO 2 . It favors the collection of photoelectrons from PbSe nanoparticles that have light absorption in wider spectral region.

Energy transfer reactions are the key for living open systems, biological chemical networking and development of life inspired nanoscale machineries. It is a challenge to find simple reliable synthetic chemical networks providing a localization of the time dependent flux of matter. In this paper we introduce a reliable, minimal reagent consuming, stable inorganic light promoted proton pump. Localized illumination was applied to a TiO2 surface in solution for reversible spatially controlled “inorganic photoproton” isometric cycling, the lateral separation of water splitting reactions. The proton flux is pumped during irradiation of the surface of TiO2 and dynamically maintained at the irradiated surface area in the absence of any membrane or predetermined material structure. Moreover we spatially predetermine a transient acidic pH on the TiO2 surface in the irradiated area with feedback-driven generation of a base as deactivator. Importantly we describe, how to effectively monitor the spatial localization of the process by in situ scanning ion selective electrode technique (SIET) measurements for pH and scanning vibrating electrode technique (SVET) for local photoelectrochemical studies. This work shows the great potential for time- and space-resolved water splitting reactions for following investigation of pH stimulated processes in open systems with their flexible localization on a surface. published

This article deals with the process of the experimental induction melting of aluminium oxide in so called cold crucible (CC). The experiment took place in a couple of steps, that were needed for a successful realisation of the melting. The first step was the designing of suitable parameters of the cold crucible regarding the depth of penetration of the eddy currents into the melted aluminium oxide and the output power of the high frequency generator for melting in the cold crucible. The process of the experiment itself then consisted in the preparation of cold crucible for melting. The overheating of the starting material to the melting point of the load. The melting of the load. The endurance of the load in steady-state at a constant temperature. The controlled cooling of the load. The removal of the ingot of aluminium oxide from the cold crucible. The article is dedicated to the process of the experiment with respect to the development of the heating losses considering the input power during the melting process in the whole induction system.

The heterogeneous catalytic ozonation on unsupported and supported oxides has been successfully tested for the removal of several refractory compounds in aqueous solution. In this work, alumina-supported nickel catalysts prepared by photodeposition and impregnation methods were compared in the catalytic ozonation of 2,4-dichlorophenoxyacetic acid (2,4-D). The catalysts were characterized by high-resolution electron microscopy and X-ray photoelectron spectroscopy. The photochemical decomposition of Ni acetylacetonate to produce Ni(OH)2, NiO, and traces of Ni° deposited on alumina was achieved in the presence of benzophenone as a sensitizer. A similar surface composition was found with the impregnated catalyst after its reduction with hydrogen at 500 °C and exposed to ambient air. Results indicated a higher initial activity and maleic acid (byproduct) concentration with the photodeposited catalyst (1 wt% Ni) compared to the impregnated catalyst (3 wt% Ni). These findings suggest the use of the photodeposition method as a simple and reliable procedure for the preparation of supported metal oxide/metal catalysts under mild operating conditions.

Mesoporous TiO 2 powder with large surface area and high porosity was prepared via template-free method of heat-stimulated oxidizing destruction of TiC by HNO 3. Anatase crystalline phase of as-prepared and annealed at 200−400 °C titania was confirmed by XRD technique. Surface nitrate-nitro groups responsible for high adsorption capacity of the TiO 2 powders were studied by FTIR spectroscopy. The annealing temperature can be used as a factor for regulation of titania morphology and structural properties. The rise in the annealing temperature higher than the temperature of nitrate-nitro groups decomposition induces the growth of TiO 2 crystallites, decreasing porosity and surface area, the drop of adsorption capacity, and improving photocatalytic activity under UV irradiation.

We obtained optically transparent n-type semiconductor films of lead zirconate titanate Pb(ZrxTi1–x)O3 by reaction of individual sols of hydrated titanium dioxide and zirconium dioxide with lead ions, followed by heat treatment at 500–800°C. We established that these films, when in contact with an aqueous electrolyte, can generate a photopotential and a photocurrent when exposed to UV radiation (250–400 nm). The average values of the bandgap energy from optical absorption and photocurrent spectroscopy data are slightly dependent on the composition of the lead zirconate titanate solid solution (they increase by 0.07–0.12 eV on going from Pb(Zr0.2Ti0.8)O3 to Pb(Zr0.52Ti0.48)O3), which may be connected with features of the band structure in these materials.

Effi cient and homogeneous surface-enhanced Raman scattering (SERS) substrates are usually prepared using lithographic approaches, physical evaporation, or in situ chemical reduction. However, these approaches are time-consuming, expensive, and very diffi cult to upscale. Alternatively, template-assisted approaches using colloidal suspensions of preformed nanoparticles have become more popular because of their low cost, fast production, and ability to be scaled up easily. One of the limitations of these methods is the dimensions of the structured surfaces. In this context, a new method for designing low-cost, up-scalable surface patterns that match building block dimensionality based on anodization of aluminum, enabling a hierarchical organization of anisotropic nanoparticles, is presented. The proposed new technology starts with anodized aluminum oxide with regular parallel linear periodicities. To produce a highly effi cient plasmonic surface, gold nanorods are assembled into parallel lines where the long axes of the Au rods are also oriented along the substrate lines, thus inducing reproducible tip-to-tip plasmonic coupling with the corresponding generation of highly active hotspots. Additionally, this advanced material presents an inherent hydrophobicity that can be exploited as a method for concentration of analytes on the surface. SERS detection is demonstrated with benzenethiol and 2-naphtoic acid.

Properties of CdS nanoparticles (NPs) grown by successive ionic layer adsorption and reaction (SILAR) method on the surface of electrodeposited ZnO films were studied by Raman, photocurrent and UV–Vis absorption spectroscopies. The CdS nanoparticles deposited at a SILAR cycle number ( N ) from 5 to 10 exhibit a broadening of the band gap ( E g ) by 0.17–0.31 eV as compared with that of the CdS particles grown at N = 30. The size quantization of the interband transition energy in CdS nanoparticles is in accordance with the Raman spectroscopic data demonstrating a considerable increase in the LO peak intensity with increasing the N from 5 to 10 as a result of transition to resonant light scattering. The spectral width of the LO peak decreases from 50 to 15 cm − 1 as the N increases from 5 to 30 reflecting a less pronounced effect of the nanoparticle surface on the phonon scattering. A large spectral width of the Raman peaks is assumed to originate from a complex structure of the CdS nanoparticles comprising crystallinity domains that can affect the phonon confinement. The photocurrent spectroscopy of ZnO/CdS heterostructures showed that the band gap of CdS NPs deposited at N > 20 is smaller by ~ 0.08 eV than that of bulk cadmium sulfide. It was concluded that this effect is not associated with photoexcitation of structural defects but rather reflects intrinsic electronic properties of SILAR-deposited CdS nanoparticles.