Russian Journal of Physical Chemistry A最新文献

Antimony sulfide (Sb₂S₃) possesses a high theoretical capacity and excellent reversibility, making it a promising anode material for lithium-ion batteries (LIBs). However, its poor intrinsic conductivity and significant volume changes during charge/discharge cycles severely limit its cycling stability and rate performance. In this study, a novel composite material was synthesized by electrostatically assembling Sb₂S₃ nanowires (Sb₂S₃ nw) onto MXene nanosheets as a potential anode material (SbSMX). The introduction of highly conductive MXene substrates enhances electron transfer between the distinct interfaces of Sb₂S₃ and MXene. Additionally, the constructed 1D–2D structure promotes ion transport within the electrode, while the mechanical flexibility of MXene effectively mitigates the severe volume expansion of Sb₂S₃. As a result, the SbSMX composite exhibits a high capacity of 813 mA h g^–1 at a current of 50 mA g^–1, stable cycling performance with a capacity of 735 mA h g^–1 after 100 cycles at 100 mA g^–1 (88% retention), and excellent rate capability, achieving 466 mA h g^–1 at a current of 3 A g^–1.

The investigation aimed to remove the Pb(II) ions from the artificial liquid using PDAC. In PDAC, PD is an abbreviation of Pithecellobium Dulce, it is a botanical name of Manila Tamarind and AC means Activated Carbon. Pithecellobium Dulce Activated carbon (PDAC) is synthesized from Pithecellobium Dulce bark and pod shell. Lead is used for cables, roofs, water and gas pipelines, mining activities, the manufacturing of acid batteries, and other structures. The industry recognizes the need for dye-treated sewage treatment because it can cause health problems for humans and animals. This research explored PDAC for its possible consumption as an eco-friendly bio-adsorbent to remove the Pb(II) ions. This investigation studied adsorption-related variables, including initial metal ion concentration, contact time, adsorption rate, temperature effects, and pH. Adsorption equilibrium was determined using Longmuir and Friendlich’s isothermal models. Current work suggests that PDAC could be employed as a low-cost adsorbent to adsorb the lead ion in an artificial liquid solution. Adsorption characteristics were determined by SEM, XRD, and FTIR studies. The results of the study demonstrated that employing an environmentally friendly adsorbent based on PDAC was a more economical and efficient way to remove Pb(II) ions from an aqueous solution.

This work presents a simulation of the magnetocaloric effect (MCE) for Mn-doped topological insulator Bi₂Se₃ thin films using phenomenological model (PM). There is a good simulation of experimental magnetization for the Bi/Mn = 12.5 and Bi/Mn = 23.6 samples in low magnetic field along 〈1(bar {1})00〉 direction. The MCE parameters for the Bi/Mn = 12.5 and Bi/Mn = 23.6 samples in low magnetic field shift along 〈1(bar {1})00〉 direction has been determined. The high Mn content in Bi/Mn = 12.5 sample enhances MCE parameters more than Mn content lower sample. The MCE for Bi/Mn = 12.5 and Bi/Mn = 23.6 samples show practical use for cooling system in very low temperatures.

The SnO₂ doped 0.2 wt % Pt/TiO₂ catalysts were prepared by wet impregnation method for the catalytic oxidation of toluene. The research focused on the SO₂ resistance and catalytic performance of Pt/SnO₂–TiO₂. The results showed that T₉₀ (the temperature corresponding conversion of 90%) was 176°C at 1000 ppm toluene concentration and weight hourly space velocity (WHSV) of 36 000 mL h^–1 g^–1. Adding 10 wt % SnO₂ to the Pt/TiO₂ catalyst reduced the adsorption capacity of the active component Pt for SO₂, enhancing the catalyst’s resistance to SO₂ poisoning. Pt/SnO₂–TiO₂ catalysts could recover to the initial activity after 9 h poisoning with 2800 ppm thiophene. The Pt/SnO₂–TiO₂ also maintained good stability during the 60 h test at 240°C with a toluene conversion larger than 99%. A series of characterization tests including XRD, H₂-TPR, and TEM revealed that Pt/SnO₂–TiO₂ possesses a mesoporous structure and a large amount of lattice oxygen, with Pt being uniformly dispersed on the carrier surface.

The energy crisis and environmental pollution have made the development of highly efficient oxygen reduction reaction (ORR) electrocatalysts a research priority to improve fuel cell performance. A simple one-pot hydrothermal method was successfully used to synthesize the Fe₃O₄@MnO₂/NC composite material, and the performance of catalyst was enhanced by adjusting the molar ratio of Fe–Mn and the addition of coconut shell carbon (CSC). The characterization results show that the Fe₃O₄@MnO₂/NC with core–shell structure has a high specific surface area (751 m² g^–1) and provides abundant active sites for ORR. The electrochemical test results show that Fe₃O₄@MnO₂/NC exhibits a superior ORR activity among the as-prepared catalysts due to strong interfacial coupling interaction. In addition, it also has a high specific capacitance, a small Tafel slope, and the lowest impedance in ORR. This not only verifies its excellent performance, but also provides a new approach and idea for developing non-precious metal ORR catalysts.

The interactions of tetra-4(4-methoxyphenoxy)phthalocyanine with pyridine, 2-methylpyridine, morpholine, piperidine, n-butylamine, tert-butylamine, diethylamine, and triethylamine in benzene and benzene–dimethylsulfoxide system have been studied. The acid-base reaction is an unusually slow process that forms proton transfer complexes that are stable over time. Their structure is proposed. The change in the reactivity of tetra-4(4-methoxyphenoxy)phthalocyanine depending on the polarity of the medium, proton-acceptor capacity, and spatial structure of the nitrogen-containing base is considered.

Due to its exceptional mechanical, optical, electrical and magnetic properties, graphene is widely used to enhance and improve the mechanical, electrical, and electromagnetic shielding properties of composite materials. In the paper, functionalized GNPs are initially prepared through sulfuric acid and nitric acid treatment for dispersion in an aqueous solution. A subsequent method using methylcellulose (MC) as a dispersant along with ultrasonic processing is then employed to further improve the dispersion of the functionalized GNPs. Various techniques, such as UV–Vis absorbance, zeta potential, surface tension and adsorption isotherm, are employed to characterize the dispersing performance of the functionalized GNPs suspension. Additionally, the dispersion mechanism of the functionalized GNPs is analyzed by means of the transmission electron microscopy (TEM). Experimental results indicate that the optimal MC concentration for dispersing functionalized GNPs in aqueous solution is 0.6 g/L. TEM images reveal that MC effectively disrupts agglomerated bundles, significantly reducing the thickness of the functionalized GNPs. The dispersing mechanism involves the diaphragm and hydrophobic effects, which prevent the GNPs from aggregating.

Experimental means of surface analysis are used to investigate in situ the adsorption and reaction of nitrogen oxide (NO) molecules on the surfaces of a model metal–oxide system. The system is formed through the controlled deposition of nickel clusters under conditions of an ultrahigh vacuum on the surfaces of α-Al₂O₃(0001) aluminum oxide thin films grown on a Mo(110) substrate. X-ray photoelectron and Auger electron spectroscopy (XPS, AES), infrared Fourier spectroscopy (IFS), and temperature-programmed desorption (TPD) data reveal a conditional 2 nm size of Ni clusters that separates the character of the electronic state of NO molecules adsorbed on their surfaces and their reactive capability. It is shown that a distinctive feature of Ni clusters with typical diameters of less than 2 nm is the adsorption of NO molecules on their surfaces in the form of (NO)₂ dimers. In contrast, adsorption produces (NO) monomers on clusters of larger size. It is concluded that this difference is the reason for the different reaction behavior of the molecules. A key difference between clusters smaller and larger than 2 nm in size is that in the former, N₂O molecules form upon heating the system and are desorbed into the gas phase. This does not occur in the latter. The formation of N₂O is due to the mutual influence of NO molecules forming (NO)₂ dimers under the action of the metal–oxide interface. Results indicate the possibility of tuning the catalytic efficiency of the metal–oxide system by varying the size of the applied metal clusters.

Nanoparticles of alkaline earth metal sulfates (AEMSes) and nanocomposites of AEMSes with sulfur nanoparticles (nanosulfur) are synthesized from polysulfide aqueous solutions (PASes) of calcium, strontium, and barium AEMs (CaS_n, SrS_n, BaS_n; n > 1). The AEM PASes are prepared in an aqueous medium at temperatures of 70 and 90°C through the reactions between metal hydroxides and sulfur. It is found that using sulfur subjected to mechanical activation in a disintegrator for synthesis allows the formation of higher AEM PAS concentrations in shorter periods of time. To identify possible mechanisms of mechanochemical recrystallization in liquid media, kinetics of particle coarsening due to the reversible aggregation of sulfur nanoparticles and AEMSes is determined via static light scattering. It is found that particles with sizes around 30 nm form initially, and the particles coarsen to sizes of several tens of micrometers over time. The rate of particle coarsening (agglomeration) constants (Q) grow along with the concentration of acid, and the optimum concentration for implementing the Q-mechanism is 10%. It is found that using surfactants (neonol; concentration, 5%) results in a multiple reduction of Q. It is also revealed that the value of Q value rises along with temperature, and the energies of activation for the coarsening of S/MeSO₄ particles are determined for the optimum range of 300–350 K. Practical aspects of the results of this work are discussed with reference to using the synthesized samples for the germination of wheat seeds, and the hydrophobicity of sulfur-containing S/MeSO₄ samples is analyzed.