Russian Journal of Physical Chemistry B最新文献

The C₆₀/Fe₃O₄/SiO₂/GeO₂ composite was synthesized containing core/shell/shell nanomaterial by layer/layer gel method. The C₆₀/Fe₃O₄/SiO₂/GeO₂ composite was characterized by X-ray diffraction, field emission scanning electron microscopy fitted through scanning electron microscopy, energy dispersive X-ray spectroscopy, fourier transform infrared spectroscopy, transmission electron microscopy and UV-visible. Magnetic behavior of the synthesized product was evaluated by vibrating-sample magnetometer. The data exhibited that magnetite composites have been properly coated. This system can be applied for recycling photosensitizing way using solar energy for water disinfection. Results were reported and for degradation organic compounds via producing a single oxygen. This approach comprises C₆₀ amino fullerene as a sensitizer for singlet oxygenation and Fe₃O₄/SiO₂/GeO₂ encapsulating magnetite nanoparticles. Fast degradation of furfuryl alcohol and methylene blue under UV-visible light exhibit that this irradiation activity of C₆₀ amino fullerene-derivatives is related to the photosensitization of single oxygen. Significant single oxygen production using C₆₀/Fe₃O₄/SiO₂/GeO₂ system causes the effective oxidation of and inactivation of MS-2 bacteriophage under UV/visible irradiation. Our results also exhibited that the variable surfaces were effective in photo-catalyst behavior of these compounds. C₆₀/Fe₃O₄/SiO₂/GeO₂ composite can also be recovered and reapplied using a strong magnetic field and the photo-catalyst particles again.

The kinetics of the thermal decomposition of the FOX-7 compound at 155°C under semiopen conditions in vessels with a volume of V = 0.8–0.9 cm³ in an air atmosphere and the degree of filling of the vessel with substances m/V = 0.03–0.72 g/cm³ has been studied by the gravimetric method. It is found that at the largest m/V, an induction period is observed in the early stages of the reaction, during which the rate of mass loss of the sample is lower by a factor of ten than the rate of decomposition of FOX-7 in the solid phase. With a decrease in m/V, the induction period is shortened and at m/V = 0.04 g/cm³ it disappears altogether. The appearance of the induction period is due to the fact that nitronic acid, which is the only product of the first stage of decomposition of FOX-7, is well adsorbed on the surface of FOX-7 crystals. At the same time, it almost completely loses its reactivity. As a result, until the end of the adsorption process, the decomposition of FOX-7 proceeds without the formation of gaseous products, and the reaction rate is not fixed by the gravimetric method suitable for studying the kinetics of the reaction at the early stages of decomposition of FOX-7.

Combustion in the 2Co–Ti–Al system is observed by high-speed video recording. It is established that combustion occurs in the frontal mode, and the process parameters are determined. The maximum rate of the increase in the combustion temperature from the moment of initiation to the maximum value reached is 2.7 × 10⁴ K/s. The front propagation velocity calculated from the video recording is 9.4 cm/s. The microhotspot mode of combustion of the reaction composition is found. The temperature dependencies of the electrical resistivity and magnetic moment of the single-phase Co₂TiAl product synthesized in the combustion mode are measured. For the synthesized Co₂TiAl sample, the Curie temperature is T_C = 120 ± 5 K and the electrical resistivity at room temperature is 1.35 μOhm m. It is shown that the electrical and magnetic properties of the Co₂TiAl alloy obtained in the combustion mode are similar to those of alloys obtained by arc melting.

The possibilities of increasing the acceleration ability (AA) of energetic materials by creating compositions combining high explosives (HEs) with a positive and negative oxygen balance are analyzed. For the calculations, three relatively new compounds are selected as HE-oxidizers: 3,6-dinitro-1,4-bis(trinitromethyl)-1,4-dihydropyrazolo[4,3-c]pyrazole; 4,4′5,5′-tetranitro-2,2′-bis(trinitromethyl)-2Н,2′Н-3,3′-bipyrazole; and 2-dinitromethyl-5-nitrotetrazole. HMX and CL-20 perform the function of HE-fuel. From the calculations it follows that the AA of HMX increases markedly with the addition of the mentioned oxidizers, and the introduction of oxidizers in the composition with CL-20 leads to a slight increase in AA.

Nano-Boron nitride compounds have displayed a great potential as anode materials for lithium ion batteries (LIBs) due to their unique structural, mechanical, and electrical properties. The measured reversible lithium ion capacities of Graphene/(h-BN)₂/Graphene(G/h-BN/G) based anodes are considerably improved compared to the conventional graphite-based anodes. In this study, the boron nitride sheet has been localized inside the graphene as an option to enhance the electrochemical ratio. Additionally, we have found the structure of G/h-BN/G can improve the capacity and electrical transport in C-BN sheets-based LIBs. Therefore, the modification of BN sheet and design of G/h-BN/G structure provide strategies for improving the performance of BN-G-based anodes. G/h-BN/G could also be assembled into free-standing electrodes without any binder or current collector, which will lead to increase specific energy density for the overall battery design. Finally, we fabricated a novel LIBs and tested our method and we found this system in similar condition using G/h-BN/G increases the voltage and amperage in LIBs. For increasing the capacity, voltage, and amperage for LIBs the composite materials play a strong role. Any theoretical studies in electrode materials (anode and cathode) of lithium ion batteries and subsequent experimental testing with the results of theory can help us to fabricate powerful batteries with low cost. Using Graphene/(h-BN)₂/ Graphene(G/h-BN/G) based anodes with a suitable composite for cathode materials exhibit high voltages and amperages compared with similar conditions of the previous LIBs.

In this study, polyaniline-derived carbon doped with nitrogen was synthesized through in-situ polymerization and high-temperature carbonization, using aniline as the raw material and ammonium persulfate as the initiator. The phase, morphology, and composition of polyaniline-derived carbon at different carbonization temperatures were characterized by thermogravimetric, transmission electron microscopy, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman, and Brunauer–Emmertt–Teller. The electromagnetic parameters of polyaniline-derived carbon with a filler content of 20 wt % were measured by a vector network analyzer, and the electromagnetic wave absorption performance was calculated using the transmission line method. The results showed that the samples had a porous morphology, and the specific surface area of polyaniline-derived carbon-650 and polyaniline-derived carbon-700 was up to 12 times greater than that of polyaniline. Furthermore, polyaniline-derived carbon-700 exhibited excellent electromagnetic wave absorption performance, with the best reflection loss at a thickness of 2.5 mm being –44.35 dB. The effective absorption bandwidth was 3.23 GHz (8.56–11.79 GHz). The effective absorption of C, X, and Ku band electromagnetic waves could be achieved by adjusting the coating thickness. The hybridization of N atoms and C atoms in polyaniline-derived carbon induced magnetism, and the synergistic effect with enhanced dielectric loss improved the electromagnetic loss capacity of the material, optimized impedance matching, and enhanced the electromagnetic wave absorption performance of polyaniline-derived carbon. The electromagnetic wave dissipation mechanism of polyaniline-derived carbon material mainly included dipole polarization, interface polarization, conductivity loss, and magnetic loss caused by N doping. The synthesized polyaniline-derived carbon is a potential electromagnetic wave absorbing material.

The parameters of the plasma of a low-pressure glow discharge in neon with microparticles, at which regions with equal values of the ion confinement efficiency in the cloud of microparticles are realized, are determined numerically. It is noted that such features are characteristic of dissipative synergetic systems controlled by the feedback. The simulation of a complex plasma of glow discharge in neon with microparticles shows that feedback in the plasma is realized through the source of the main losses of its energy—a cloud of microparticles. Controlling the discharge parameters by changing the concentration of microparticles in the cloud makes it possible to control the concentration of the ions in the plasma.

Polyaniline is a conducting polymer with a wide variety of applications. In the recent years, exploring the different avenues for the synthesis of polyaniline has gained immense popularity among the researchers. This study focuses on the experimental investigation and subsequent data modeling to determine the kinetics of chemical (oxidative) polymerization of aniline with ammonium persulfate as an oxidant in aqueous hydrochloric acid solutions at 277 K. The concentration of the polyaniline formed was determined using colorimetry. The effect of different initial concentrations of oxidant/monomer from 0.010–0.025 M on the rate of polymerization was observed. The polymerization kinetics at various initial oxidant to monomer mole ratios from 1–2.5 was also investigated. Using a well-established kinetic rate expression, the reaction rate constants were determined that best fitted the experimental data. Further, the polyaniline concentrations were predicted using the kinetic parameters with an absolute average relative deviation ranging from 4 to 17%.

The lack of successful p-type semiconductor oxides delays the future implementation of metal oxide semiconductor photovoltaic and thermoelectric devices. In the group semiconducting compounds, copper oxides present promising electrical, optical and manufacturing features that establish this family of materials suitable for p-type semiconductor applications. In this work, we focused on the growth of alkali doped CuO thin films, aiming for enhancements of their structural, optical, electrical and thermoelectric response. During this study, we highlight the effect of copper oxide doped with alkali ions (Li⁺, Na⁺, K⁺) prepared by the sol-gel technique and deposited on glass substrates. The effective substitution of the alkali elements into CuO lattice is analyzed by physical characterization i.e. X-ray diffraction, the spectra matched well with the monoclinic phase. Ultraviolet-visible spectroscopy showed that the band gap energy tends to increase with alkali doping and achieves a maximal value with (Li⁺) doping. Among the alkali ions (Li⁺) was the most effective to enhance electrical conductivity. Conductivity type showed by thermoelectric/hot prop confirmed the P-type conductivity. The maximum power factor PF was (9.776 × 10^–10 W m^–1 K^–2) for Li doped CuO. The present work is worth significant for thermoelectric devices.

The patterns of catalytic ignition of deuterium–air mixtures above the surface of metallic rhodium at pressures of 1–2 atm and temperatures of 20–250°C using hyperspectrometers in the range of 400–1650 nm and high-speed filming have been established. It is established that the catalytic ignition of deuterium–air mixtures in the studied temperature range is observed at a deuterium content of more than 12%; and at a deuterium content of less than 12%, only intense heating of the catalytic wire is observed. It is shown that the initial ignition source occurs on the surface of the reactor. In subsequent experiments, under the same conditions, the location of the original center changes. It has been found that the upper limit of the catalytic ignition above the D₂–air mixture is noticeably lower than the lower ignition limit of the H₂–air mixture. Thus, D₂ is more combustible than H₂ over the surface of Rh at a pressure above 1 atm. The limits of catalytic ignition are even lower than 20°C, although the flame velocity in hydrogen–air mixtures and the flame temperature in these mixtures of the same composition are much higher than those of deuterium–air mixtures. The nature of the detected kinetic inverse isotope effect is probably determined by the high level of activity of rhodium deuteride in relation to the deuterium oxidation reaction.