Russian Journal of Physical Chemistry B最新文献

Criegee Intermediates (CIs), or carbonyl oxides, arise due to ozonolysis of alkenes, which are typical anthropogenic air pollutants. They play an important role in many chemical reactions occurring both in the lower and in the upper atmosphere of the Earth. Dissociation products of CIs may interact with other atmospheric compounds to produce hydroxyl (OH) radicals and other chemically active substances. Probably, these reactions are responsible for formation of nitric and sulfuric acids in the atmosphere. In the troposphere, CIs dissipate their initial internal energy through collisions with the bath atmospheric gases, and interact with chemically active atmospheric molecules. In the stratosphere and mesosphere carbonyl oxides can decay into chemically active fragments, which then trigger multiple secondary reactions. In this work the main dissociation reactions of (CH₃)₂COO Criegee intermediate molecule were studied. For that, ab initio B3LYP/CCSD(T) potential energy surface (PES) calculations have been performed followed by the estimation of rate constants and products yield by the RRKM method. It was found that the most probable dissociation products are OH, CH₃COCH₂, CH₃, and CH₃OCO radicals, as well as ethane and CO₂.

Tungsten trioxide (WO₃) is renowned for its outstanding electrochromic properties, which can precisely regulate transparency under external electric fields, providing an innovative solution to the increasingly severe energy consumption problem. The material, with its excellent chemical stability and multi-functionality, has attracted widespread attention in electrochromic devices, electronic displays, and smart windows, and has achieved remarkable achievements in domestic and international research. This paper reviews the electrochromic mechanism and efficient preparation techniques of tungsten trioxide-based composite materials, particularly emphasizing the effectiveness of strategies such as element doping, composite modification, and morphology control to enhance its electrochromic performance. At the same time, the article also points out the challenges in the preparation and practical application of WO₃ and looks forward to the innovative research and development and application prospects of tungsten trioxide-based multifunctional composite materials in the future.

The research on lanthanide selenides has experienced rapid developments during the past few years, largely due to their importance to basic research and promising applications originated from the unique 4f-electronic configuration. The structural, mechanical, electronic, and optical properties of PrSe₂ have been investigated by means of first-principle calculations. In terms of electronic properties, detailed calculations and analyses were conducted on the band structure and density of states. We also calculated the real and imaginary parts of the dielectric function, absorption coefficient, extinction coefficient, reflectivity, and refractive index to analyze important optical properties in depth. PrSe₂ has shown the good characteristics required for photovoltaic applications. Our results indicate that compound PrSe₂ has some attractive electronic, and optical properties, making it suitable for engineering and device applications.

In this investigation a sol-gel technique by using tartaric acid as a chelating agent was used to prepare one of the rare earth orthoferrite PrFeO₃ nanoparticles. The prepared PrFeO₃ nanoparticles were characterized using different analytical techniques such as X-ray diffraction, scanning electron microscopy, Raman spectroscopy and UV-visible absorption spectroscopy. Thermo-gravimetric analysis data was employed for calcining the PrFeO₃ synthesis sample, and there was no weight loss (%) observed above 800°C. X-ray diffraction technique reviles the formation of single phase of PrFeO₃ with Orthorhombic crystal structure. Lattice parameters, dislocation density of the synthesized PrFeO₃ nanoparticle were also calculated using the X-ray diffraction data. The uniform spherical shaped particles were observed through scanning electron microscopy analysis and it average grain size was found to 350 nm. The calculated optical bandgap of PrFeO₃ nanoparticle was found to be 1.97 eV. X-ray photoluminescence spectra suggest that, the Pr is existing in +3 oxidation state and Fe is exist in mixed oxidation states (+2 and +3).

Hybrid and advanced multifunctional composite materials have been extensively investigated and used in various applications. Alkali metals of rubidium and cesium are studied through doping in lithium, sodium or potassium ion batteries. A vast study on H-capture by LiRb(Sn–Si)O₂, LiCs(Sn–Si)O₂, NaRb(Sn–Si)O₂, NaCs(Sn–Si)O₂, KRb(Sn–Si)O₂, KCs(Sn–Si)O₂, was carried out including using density fucntional theory (DFT) computations at the CAM–B3LYP–D3/6–311+G(d, p) level of theory. The hypothesis of the hydrogen adsorption phenomenon was figured out by density distributions of charge density differences (CDD), total density of state (TDOS), electron localization function (ELF) for nanoclusters of LiRb(Sn–Si)O₂–2H₂, LiCs(Sn–Si)O₂–2H₂, NaRb(Sn–Si)O₂–2H₂, NaCs(Sn–Si)O₂–2H₂, KRb(Sn–Si)O₂–2H₂, KCs(Sn–Si)O₂–2H₂. The oscillation in charge density amounts displays that the electronic densities were mainly placed in the edge of adsorbate/adsorbent atoms during the adsorption status. As the benefits of lithium, sodium or potassium over Sn/Si possess its higher electron and hole motion, permitting lithium, sodium or potassium devices to operate at higher frequencies than Sn/Si devices. A small portion of Rb or Cs entered the Sn–Si layer to replace the Li, Na or K sites might improve the structural stability of the electrode material at high multiplicity, thereby improving the capacity retention rate. Among these, potassium-ion batteries seem to show the most promise in terms of Rb or Cs doping. The results have shown that the cluster of NaRb(Sn–Si)O₂, LiRb(Sn–Si)O₂, KRb(Sn–Si)O₂ may have the most tensity for electron accepting owing to hydrogen grabbing. the TDOS curve for KRb (Sn–Si)O₂ and KRb (Sn–Si)O₂–2H₂ nanoclusters have shown the maximum density of state of ≈24 around –0.30 a.u. Tin-silicon heterocluster, with advantages of earth abundance, environmental friendly, chemical stability, and less toxicity can be used in alkali metal-ion batteries, piezoelectric, optoelectronics, and sensors. This research article addresses the challenges and prospects of developing advanced energy storage devices and suggests potential directions for future research.

Currently, LiCoO₂ is widely used as cathode in lithium ion batteries (LIBs). However, the relatively high cost and safety problems cause serious approaches for improving the LIBs. Partial substitution of Cobalt by mixing with transition metals, such as Fe, Mn and Ni, can lower costs and improve battery efficiency and also safety. The objective of this research is to prepare a composite with lower cost and better cyclability than the other cathode materials in lithium ion battery. A ternary composition with high efficiency and low cost containing LiFeO₂ and LiCo_1/3Ni_1/3Mn_1/3O₂, was applied instead of pure LiCoO₂ to reduce usage of the percentage Co amount in cathode materials of LIBs, consequently a benefit would be yielded by reducing the cost of cobalt and also by removing its toxic effect in LIBs the environment will be safe. In this study, we synthesized ten samples from mixture of xLiFeO₂, yLiCoO₂, and (1 – x – y)LiCo_1/3Ni_1/3Mn_1/3O₂ compounds for preparing suitable cathode electrodes with high initial discharge capacity, large cyclability and inexpensive cost instead of traditional cathode materials. As a result by using Raman Analysis, X-ray diffraction, and electrochemical analyzing, we found that the LiNi_3/18Co_6/18Mn_3/18Fe_3/18O₂ composite has high efficiency and best performance in viewpoint of initial capacity, cyclability, charge capacity, and discharge capacity among these ten composites. Conduction has been one of the main barriers to further improvements in Li-ion batteries and is expected to remain so for the foreseeable future. In an effort to gain a better understanding of the conduction phenomena in Li-ion batteries and enable breakthrough technologies, a comprehensive survey of conduction phenomena in all components of a Li-ion cell incorporating experimental, and simulation studies, is presented here. Our target of this work is based on fabricating lithium ion batteries with the most performance. This study could help in the development of analytics for products where the lithium ion battery will be used as a component. Also it will help in understanding the optimal usage conditions for their long cycle life. Further, it can be used in designing electronics and battery management systems.

The world encounters an increasing challenge for adequate clean water owing to threats coming from enhancing request and reducing supply. In nanoscale, zinc oxide and zinc sulfide have indicated antimicrobial properties which make its potential great for different applications. We employ first-principles calculations to investigate the structural stability and electronic properties of cubic zinc oxide (ZnO) and zinc sulfide (ZnS) heteroclusters with H₂O molecules adsorbed on them. A comprehensive investigation on H₂O grabbing by ZnO/ZnS heteroclusters was carried out using density functional theory (DFT) computations at the Coulomb-attenuating method–Becke, 3-parameter, Lee–Yang–Parr with Dispersion–corrected (CAM–B3LYP–D3/6–311+G(d, p)) level of theory. The notable fragile signal intensity close to the parallel edge of the nanocluster sample might be owing to H/OH binding induced non-spherical distribution of ZnO or ZnS heterocluster. The hypothesis of the energy adsorption phenomenon was confirmed by density distributions of charge density differences, total density of states and molecular electrostatic potential for ZnO/ZnO(H₂O) or ZnS/ZnS(H₂O). A vaster jointed area engaged by an isosurface map for H/OH adsorption on ZnO or ZnS surface towards formation of ZnO(H₂O) or ZnS(H₂O) complex. Therefore, it can be considered that zinc in the functionalized ZnO or ZnS might have more impressive sensitivity for accepting the electrons in the process of H/OH adsorption. It is considerable that when all surface atoms of ZnO or ZnS are coated by OH and H groups, the semiconducting behavior is recovered.

An electroosmosis micromixer is an essential element within microfluidic systems, designed to effectively facilitate the mixing of fluids at the microscale. These devices are essential across various scientific disciplines, such as chemistry, biology, and medicine, due to their ability to manipulate minute volumes with extraordinary precision and minimal reagent loss. Electroosmosis can be defined as the movement of fluids through micro/nano-channels, driven by an externally applied electric field. In the current investigation, a micromixer that is driven by electroosmosis phenomena, has been developed to combine two disparate fluids, which are introduced into the system through separate inlets, resulting in a combined microchannel. To improve this mixing system, a sinusoidal electric potential is systematically applied across the triangular-shaped electrodes, characterized by a peak value of 0.1 V and an operational frequency of 8 Hz. The simulation results obtained from this configuration indicate that the micromixer demonstrates an exceptional mixing efficiency approaching a value of 0.96, thereby highlighting its considerable potential for beneficial applications across a diverse array of fields, particularly within microfluidics, biochemistry, and biomedical sciences.

The mechanism of participation of MnCl₂, ZnCl₂, CdCl₂ and PbCl₂ salts in different stages of lipid peroxidation (LP) processes in liposomes formed from natural lipids (lecithin of soybeans) in distilled water was studied, using mathematical processing of UV-spectra of liposomes and their mixtures of metal ions by the Gauss method in combination with the study of the effect of metal ions on spontaneous aggregation of liposomes (dynamic light scattering method) and the intensity of bacterial bioluminescence. While all metal ions at the studied concentration of 10^–4 mol/L are considered as damaging substances for biological systems, the degree of toxicity of both pollutants (Pb²⁺ and Cd²⁺) and biogenic manganese and zinc ions is due to differences in their participation in the regulation of LP processes. Thus, the biological effectiveness of Cd²⁺ is mainly related to its ability to initiate LP. The Pb²⁺ affects its inhibitory effect on LP by forming complexes with the polar groups of phospholipids, the diene conjugates, and the ketodiene fatty acids found within liposomes. Mn²⁺ inhibits LP by forming complexes with ketodiene fatty acids and phosphate groups of phospholipids, while Zn²⁺ affects the structural state of liposomes by forming complexes with phosphate groups of phospholipids and diene conjugates.

Carbon based materials have the characteristics of light weight, adjustable dielectric and stable performance, so they have become the most concerned wave absorbing materials. In this paper, phenolic resin was prepared with sodium chloride as template, and then L-lysine as nitrogen source was used to add nitrogen into phenolic resin, and the final nitrogen doped hollow cubic carbon material was obtained by etching after carbonization. During the experiment, the material with excellent wave absorbing performance was prepared by controlling the doping amount of nitrogen element. Finally, it was found that the nitrogen-doped hollow cubic carbon wave absorbing material could obtain the best reflection loss of –50.26 dB and the maximum effective bandwidth of 4.68 GHz at the extremely low load of 1.75 wt %. The one-component wave absorbing material can have good absorbing performance under very low load, which can become the best candidate material for lightweight and efficient electromagnetic wave absorber without adding other materials, and achieve the purpose of “wide, strong, light and thin.”