Russian Journal of Physical Chemistry B最新文献

This paper presents the synthesis of a ZnO-doped SiO₂–TiO₂ nanocomposite using the sol-gel method. The spin-coating technique was employed to deposit the nanocomposite thin film onto a glass substrate. The ZnO doping ratio varied from 0 to 5%, and the thin films were calcined at temperatures ranging from 100 to 300°C for 2 h in air. FE-SEM images indicate that the films exhibit homogeneous, crack-free surface morphologies. The hardness of the ZnO-doped TiO₂–SiO₂ nanocomposite thin films is influenced by several factors, including ZnO doping concentration, heating temperature, and the molar ratio of [Ti]/[Si]. The ZnO-doped TiO₂–SiO₂ nanocomposite thin films show high transmittance in the visible region, are uniformly dispersed on the membrane surface, and have an average size of approximately 20–50 nm. These nanocomposite thin films can serve as protective coatings, enhancing UV resistance and scratch resistance while maintaining desirable required aesthetics.

The structural, electronic, optical and elastic properties of Sc_xY_1–xN (0 ≤ x ≤ 1) alloys in rocksalt phase have been investigated using first-principles method based on density functional theory (DFT). The lattice constants decrease while the bulk modulus increases with Sc concentration increasing. Result shows that with the increase of Sc constituent, the band gap of Sc_xY_1–xN increases and the band structure for x = 0.25, 0.50 and 0.75 are direct gap semiconductors. The density of states and optical constants such as complex dielectric function, extinction coefficient, refractive index and absorption coefficient are also calculated and analyzed in detail. The sound velocities and the Debye temperatures are calculated for all the Sc_xY_1–xN alloys using the calculated elastic constants and elastic modulus. The effect of Sc composition on elastic constants C_ij, elastic modulus (bulk modulus B, shear modulus G, Young’s modulus E), Poisson’s ratio (ν) and B/G are investigated for all the Sc_xY_1–xN alloys. The longitudinal and shear wave velocities (v_s, v_l) and Debye temperature θ_D are calculated for all the Sc_xY_1–xN alloys using the calculated elastic constants and elastic modulus. Further, elastic wave velocity (v_s, v_l) and Debye temperature all monotonically decrease with increasing Sc concentration. The agreement between the present results and the known data that are available only for ScN and YN is generally satisfactory. In addition, our results for the narrow band gap of Sc_xY_1–xN alloys (0 < x < 1) are predictions.

The additive approach allows us to bypass quantum mechanics problems and directly estimate an individual chemical substance’s macroscopic physical and chemical properties through its atomic characteristics. The fundamental idea of the approach is that these properties depend entirely on the atomic-molecular structure of the substance and are found by simple additive summation of the properties of the atoms. The concept of statistically averaged equipotential (equigeometric) radius is firstly introduced, a normative basis that considers the stereometry of an actual molecule. This fixes the lower level of the corridor of estimation errors. The practicality of the approach is that it does not require a computer and takes a reasonably short calculation time.

The control of crystallization process of perovskite plays an important role in the performance improvement of PSCs (perovskite solar cells). In this work, we prepared perovskite by the addition of lead thiocyanate (Pb(SCN)₂) to a perovskite precursor solution and investigated its effect on the performance of PSCs consist of FTO/TiO₂/ZrO₂/carbon structure. It was found that the crystallization process of perovskite by Pb(SCN)₂ addition was very slow, which was confirmed by XRD analysis that it took at least 24 h to complete the conversion to perovskite. The maximum efficiency of PSCs with carbon electrode manufactured using Pb(SCN)₂ additive was 15.6%. The analysis showed that Pb(SCN)₂ addition contributes to the performance improvement of devices by delaying the crystallization rate of perovskite, increasing the crystal size and suppressing the non-radiative recombination.

In this study, two novel α-aminophosphonic acids (HAP1 and HAP2) derived from 3-aminopropanol and 4-aminobutanol, respectively, were synthesized via modified Irani-Moedritzer reaction, under microwave conditions. It was found that the synthesis method gave a higher yield (in excellent yields (>90%) within very short reaction times (<10 min) in comparison with conventional method. The structures of the obtained molecules were confirmed by different physicochemical methods (FT-IR, ¹H-NMR, ³¹P-NMR and Elemental Analysis). In order to know the effect of the main side chain length and the phosphonomethyl moiety addition on the structures, electronic, vibrational and thermodynamic proprieties, the Density Functional Theory (DFT) at the B3LYP/6–31G(d, p) level was used. Moreover, a comparative study between the obtained molecules (HAP1) and (HAP2) has been made to determine different properties of these products and analyzed by means of the HOMO–LUMO properties. The global reactivity descriptors, Mulliken atomic charges and dipole moment of the two molecules were also calculated and discussed. In addition, the synthesized molecules were screened for their antioxidant potential using: ABTS⁺ and DPPH which exhibited excellent activity, particularly with compound (HAP2) for all the antioxidants assays. Furthermore, the synthesized compounds were evaluated for their in vitro antibacterial activity against two Gram-negative (E. coli and P. aeruginosa) and two Gram-positive bacterial strains (S. pyogenes and S. aureus) by disk diffusion method. Among synthesized compounds, compound HAP1 showed potent inhibitory activity compared to standard antibiotic. The investigated molecules may be used as lead molecules for designing new therapeutically effective antibacterial and antioxidant agents.

In the present work, we demonstrate a versatile Liquefied petroleum gas sensor using reduced graphene oxide thin films fabricated by thermal annealing of graphene oxide at 250°C. The morphological modification, structural analyses and sensing behavior of the films have been investigated using UV-visible absorption spectrometry, X-ray diffraction, Fourier transform infrared, atomic force microscopy and current-voltage measurements. The measurement of the reduced graphene oxide thin film electrical properties, when exposed to different concentrations of liquefied petroleum gas, exhibit a variety of outstanding features, including excellent electrical conductivity, fast response time, good recovery behaviors, high sensitivity, and remarkable stability. These excellent properties make it ideal probe for gas sensor applications.

Water contamination constitutes a substantial global issue that affects the environment. The discharge of manufacturing waste substantially contributes to this issue. Adsorption materials have demonstrated huge potential in wastewater treatment. For the efficient removal of an anionic dye, fast green (FG), a polypyrrole-coated cobalt ferrite (PPy@CoFe₂O₄) magnetic nanosorbent is prepared via in-situ polymerization of pyrrole on CoFe₂O₄ nanoparticles. Scanning electron microscopy (SEM) analysis demonstrated spherical nanoparticles with sizes around 50 nm, which was further supported by XRD data. FTIR spectra identified characteristic peaks in the 400–600 cm^–1 range, confirming the presence of M–O bonds and indicating the formation of spinel ferrite. Zeta-potential study showed that the surface charge of PPy@CoFe₂O₄ is negative in alkaline media and positive in acidic media. The adsorption system adhered to a pseudo-second-order kinetic model, with the equilibrium time being determined at 50 min. The Langmuir model accurately simulated the adsorption isotherms. Under optimal conditions (pH = 5.0, volume –25 mL, adsorbent dose –100 mg, and at 303 K temperature), the maximum monolayer adsorption capacity of PPy/CoFe₂O₄ is 85.25 mg g^–1. Even after five desorption-adsorption cycles, the removal efficiency remained above 90%. Negative ΔG° and ΔH° indicate spontaneous FG adsorption onto PPy/CoFe₂O₄, decreasing with temperature. These findings demonstrate that the PPy/CoFe₂O₄ composite is a highly effective adsorbent with broad potential applications for treating wastewater containing anionic dye.

Through thermal explosion reaction, a composite coating was formed on the surface of cubic boron nitride particles using Ti/carbon black/polytetrafluoroethylene/cubic boron nitride powders as raw materials. The results indicate that after the thermal explosion reaction, the coating on the surface of cubic boron nitride particles mainly comprised Ti, TiC, TiN, and TiB₂ phases. When the cubic boron nitride content in the raw material was less than 50%, its surface was well coated. The coating had a relatively small structure composed of a large number of nanoscale particles. A reaction mechanism underlying the thermal explosion-induced surface coating of cubic boron nitride had been proposed.

In order to study the technology of liquid CO₂ phase transition explosion and optimize the thermal safety performance of the initiating agent formulation, a reference was made to the classic British formula. The optimized formulation of the initiating agent obtained by using the MATLAB calculation program was tested for its combustion characteristics, sensitivity characteristics, thermal decomposition characteristics and thermal stability performance by ignition test, sensitivity test, thermogravimetric analysis, differential scanning calorimetry, and temperature resistance test. The thermodynamic data obtained were theoretically calculated by the Ozawa method, and the long-term use temperature of the initiating agent was calculated according to empirical formulas. The initiating agent cannot be ignited in the open air. It is feasible to design an optimized formulation by accurately controlling the content of ammonium oxalate, which can also regulate its thermochemical stability to a certain extent.

This study focuses on optimizing the performance of MAPbI₃/({text{CuI}}{{{text{n}}}_{x}}{text{G}}{{{text{a}}}_{{1 - x}}}{text{S}}{{{text{e}}}_{2}}) heterojunction solar cells to achieve enhanced efficiency through computational simulations using SCAPS-1D. We investigated the influence of variations in the Ga/Ga + In ratio within(~{text{CuI}}{{{text{n}}}_{x}}{text{G}}{{{text{a}}}_{{1 - x}}}{text{S}}{{{text{e}}}_{2}}) the absorber layer on device performance. The simulation results revealed a direct correlation between the gallium content and the J–V parameters; we identified an optimum ratio that maximized the efficiency. Subsequently, we explored the effect of absorber layer thickness, acceptor density, interface defects, and operating temperature on device performance, focusing on the optimum gallium content in the ({text{CuI}}{{{text{n}}}_{x}}{text{G}}{{{text{a}}}_{{1 - x}}}{text{S}}{{{text{e}}}_{2}}) layer. Under optimized conditions, the results indicate that adjusting the gallium content can significantly enhance the designed solar cell performance, resulting in impressive characteristics, including an open-circuit voltage of 1.2847 V, a short-circuit current density of 25.2992 mA/cm², a fill factor of 89.54%, and an overall efficiency of 29.10%. These findings highlight the crucial significance of the gallium content and provide valuable insights for advancing sustainable photovoltaic technologies.