Introduction:
Titanium-based nanostructures are attracting interest due to their significant application potential in medicine, electronics, electrical engineering and energy storage systems. They are most often obtained by top-down methods, which require the use of toxic reagents and multi-stage etching processes. In this work, titanium and carbon-based coatings were developed using an innovative hybrid method combining magnetron sputtering (MS) with radio frequency plasma-enhanced chemical vapour deposition (RF-PECVD).
Methods:
Nanolayered Ti/C coatings were fabricated on silicon substrates using a hybrid method. Titanium layers were deposited by magnetron sputtering at a constant target power of 0.23 kW, while carbon layers were deposited by RF-PECVD at a constant negative self-bias potential of −400 V. The individual sample series differed in the deposition time of the layers, enabling control of their thickness. Selected samples were subsequently annealed in a vacuum furnace at 500 °C for 1 h. Both the as-deposited and annealed samples were characterized using Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS).
Results:
Optical profilometry measurements confirmed the formation of coatings with thickness in the nanometer range. The obtained results indicate that the hybrid MS/RF-PECVD method enables the fabrication of nanolayered Ti/C systems with controlled layer thickness and uniform morphology. Raman spectra revealed bands characteristic of carbon structures in the 1300–1500 cm⁻¹ range (D and G bands). Signals in the region of ~300 cm⁻¹ were also detected, which may be associated with the presence of titanium compounds.
Conclusions:
Results confirm that the hybrid MS/RF-PECVD method represents a promising approach for the fabrication of controlled nanolayered Ti/C systems, which may serve as a platform for the synthesis of new two-dimensional materials.

This study investigates the mechanical activation of coal gangue via vibratory ball milling for durations ranging from 1 to 120 minutes and its subsequent application as a geopolymer precursor. Coal gangue, a significant industrial byproduct, requires precise structural modification to overcome its inherent chemical inertness. The evolution of the mechanically activated coal gangue’s physical properties including particle size distribution (PSD), specific surface area (SSA), and surface morphology was systematically characterized using Laser Diffraction and Scanning Electron Microscopy (SEM).

The influence of specific grinding energy on chemical reactivity and the resulting geopolymerization process was further evaluated through Fourier-transform infrared spectroscopy (FT-IR) and uniaxial compressive strength. A quantitative correlation was established between the specific grinding energy and characteristics of the activated coal gangue, and the final mechanical performance of the resulting geopolymer binders.

The experimental results demonstrate that while initial grinding significantly enhances reactivity by increasing the specific surface area , prolonged grinding beyond an optimal kinetic limit induces undesirable particle agglomeration. This over-grinding phenomenon leads to a reduction in effective surface area, which negatively impacts the dissolution rate and subsequent geopolymer strength. These findings provide a critical quantitative basis for optimizing grinding conditions, balancing energy consumption against material performance. Ultimately, this research offers a pathway for the enhanced value-added utilization of coal gangue in the production of sustainable, low-carbon geopolymer materials

Metal–organic frameworks of HKUST-1 {[Cu²⁺₂(BTC)^3-₂)(Solv)_x]×G_y}_n (CuBTC;Solv.-solvent in framework; G-guest in voids) are composed of Cu²⁺ dimers linked by benzene-1,3,5-tricarboxylate (BTC). CuBTC exhibits cubic symmetry (sp.gr.Fm3m,Z=16), an ordered 3D pore structure, high specific surface area, thermal stability, adsorption capacity, and selectivity. The use of CuBTC is related to technological feasibility: CuBTC can be produced in required quantities with reduced cost and high performance characteristics, which became the motivation for this study.

Synthesis (reagents: Cu(NO₃)₂×3H₂O, H₃BTC; solvents: water, ethanol, DMF) was carried out using the solvothermal method (SA;t=130°C,t=8 h;n=1 gram-product weight) and express method in a water bath (WB/n;t=84°C,t=3 h;n=4 and 10grams) with thermal treatment (t=200°C, t=5 h) of WB/10 to open the active centers in the structure of dehydrated/desolvated WB/10D.

XRD, IR spectroscopy, SEM/EDX and BET show changes in the microstructure and morphology/habitus from a large number of octahedra (10–20 mm) and a small number of shapeless crystals in WB/4 to octahedra, intergrowths and twins (from 10 to 60 mm) in WB/10. A decrease in specific mesoporous surface areas from 893m²/g in SA to 810m²/g in WB/10 was revealed. A significantly smaller amount or even absence of G in WB/10D compared to WB/10 was found, and the compositions of WB/4 and WB/10 are similar.

Low-temperature adsorption activity for N₂ is higher for SA (~272cm³/g) compared to WB/10 (~258cm³/g); the conversion of allyl alcohol and hydrogen peroxide to glycidol is higher for WB/10D than for WB/10, but the selectivity of GD for HP is significantly higher for WB/10. This indicates different mechanisms of catalytic process due to changes in the nature of active centers.

Funding: Ministry of Science and Higher Education of the Russian Federation, grant number FSFZ-2024-0003.

Iron oxide nanoparticles (IONPs) have attracted significant attention in recent years due to their versatility and facile synthesis. They are considered a promising platform for the development of novel antimicrobial delivery systems, particularly in the context of the emerging antibiotic-resistant pathogens that continue to pose a global threat. This study aims to investigate the potential antimicrobial efficacy of IONPs, synthesized using the co-precipitation method and functionalized with anthocyanins, which act as bioactive agents that have been extracted from
blackcurrants (Ribes nigrum), forming a core–shell architecture. Anthocyanins are pH-dependent phenolic pigments, naturally occurring in various berries and fruits, that exhibit a strong antioxidant activity, strongly associated with antimicrobial and anti-cancer properties.
The resulting bio-composite was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which confirmed its spherical morphology, with an average particle size of approximately 10 nm, while Fourier-transform infrared spectroscopy (FTIR) demonstrated the successful organic coating of the nanoparticles. Furthermore, the antimicrobial activity of the functionalized IONPs was assessed against both Gram-positive and Gram-negative bacteria using the disk-diffusion method and broth microdilution assays in 96 microtiter plates. The obtained results highlight the potential of anthocyanin-functionalized IONPs as sustainable, plant-derived antimicrobial agents.
By combining natural bioactive compounds with biocompatible nano-delivery systems, this approach offers a promising strategy for developing alternative antimicrobial therapies capable of overcoming resistance mechanisms.

In this study, a magnetic composite based on zeolite, functionalized with magnetite (Fe₃O₄) and polypyrrole (PPy), was developed to obtain a material combining magnetic properties with hydrophobic–oleophilic characteristics. Zeolite was used as a support material due to its porous structure and high specific surface area, which facilitates the uniform dispersion of Fe₃O₄ nanoparticles. These nanoparticles are responsible for the magnetization of the composites and enable rapid and efficient separation under an external magnetic field. Functionalization with polypyrrole modified the surface properties, providing hydrophobicity and enhanced affinity for nonpolar organic compounds and petroleum products.

The obtained composite was evaluated for the recovery of used motor oil from the water surface, showing an absorption efficiency of 90–95%. These results demonstrate the high potential of the developed magnetic composite material for applications in oil spill remediation and aquatic environment depollution. In addition, the magnetic nature of the material allows its easy collection after the adsorption process, reducing secondary contamination and facilitating possible reuse of the composite.

The combination of zeolite’s porous framework with the magnetic response of Fe₃O₄ and the conductive polymer coating provided by polypyrrole contributes to improved stability and adsorption performance. Furthermore, the material exhibits good structural stability and maintains its functional properties during repeated contact with oil–water mixtures. Such characteristics highlight the potential of this composite as an efficient, low-cost, and environmentally friendly solution for the treatment of contaminated water surfaces and the mitigation of pollution caused by petroleum-based products.

BaTiO₃/graphene/PVA hybrid composite films were fabricated by a solution-casting approach and systematically investigated to establish crystal–polymer interface effects on their structural and functional behavior. X-ray diffraction confirmed the presence of tetragonal BaTiO₃ (P4mm) nanocrystallites with sizes of 13.4–17.0 nm and microstrain ε ≈ 0.114%, embedded within an amorphous PVA matrix and accompanied by a weak graphene (002) reflection. Semi-quantitative RIR evaluation revealed a three-phase composition of BaTiO₃ ≈ 20.7 wt%, graphene ≈ 17.5 wt%, and PVA ≈ 61.8 wt%. SEM imaging showed a heterogeneous layered morphology with platelet-like regions (23–42 μm) and localized agglomerates, indicating non-uniform filler dispersion and high interfacial area density. FTIR and Raman spectra confirmed the coexistence of PVA vibrational modes, graphene domains, and BaTiO₃ lattice vibrations, evidencing strong interactions at phase boundaries.

Optical measurements demonstrated wide band-gap behavior with direct and indirect transitions at 6.38 eV and 6.06 eV, respectively, and ~50% visible-range transparency. Dielectric spectroscopy revealed pronounced Maxwell–Wagner–Sillars interfacial polarization at low frequencies, decreasing dielectric losses with increasing frequency, and AC conductivity transitioning from quasi-DC behavior to dispersive hopping at high frequencies. Temperature-dependent permittivity and conductivity further confirmed thermally activated interfacial and carrier-transport processes.

These results show that crystallite size, phase distribution, and interfacial heterogeneity dominate the functional response of the BaTiO₃/graphene/PVA hybrid, demonstrating its potential for transparent dielectric layers and UV-optoelectronic components within advanced composite crystalline material platforms.

This research addresses the critical challenge of energy conversion and hydrogen storage as a key low-carbon energy carrier for modern transportation. The primary objective of this study is to provide a comprehensive analysis of the thermomechanical properties and molecular-level interaction mechanisms of a novel composite material, designed to optimize the operational performance and enhance the structural integrity of hydrogen transport pipelines and storage vessels within next-generation energy systems. This study involved the fabrication of five composite series with reduced graphene oxide (rGO) contents ranging from 0 to 2 wt%, utilizing a strategic partial curing agent substitution to examine its impact on the cross-linking density and thermomechanical performance of the epoxy matrix. A comprehensive experimental methodology was applied, including static flexural (ISO 178) and compression (ISO 604) strength tests, Vickers hardness measurements (ISO 6507), and differential scanning calorimetry (DSC) analysis. These empirical investigations were complemented by advanced quantum chemical simulations using the PM6 semi-empirical method within the Scigress software, facilitating the analysis of macromolecular electron distribution and physicochemical interactions at the epoxy–graphene interface. The results demonstrate a dual effect of the nanofiller: at low concentrations (0.25 wt%), increased material plasticity was observed due to reduced cross-linking density, whereas higher concentrations (≥ 0.5 wt%) led to significant mechanical reinforcement and restricted polymer chain mobility. Although rGO integration reduced flexural strength by 1.3-6.6%, the 2 wt% loading enhanced Vickers hardness by 7.5% and Young’s modulus by 6.9%, reducing deflection by 22.2%. Integrated DSC and mechanical analyses identified 0.5 wt% as the critical threshold, where peak crystallinity optimized compressive strength to 89.7 MPa, notwithstanding a 5°C depression in the glass transition temperature (Tg). This phenomenon, combined with the "labyrinth effect" providing a superior diffusion barrier, significantly enhances the durability of hydrogen installations.

The demand for batteries for energy storage for mobility and stationary energy storage system has increased significantly in recent years and sustained growth is expected due to the insertion of renewable energies, the increase in electric vehicles and energy efficiency. Lithium-ion batteries have high gravimetric and volumetric energy density. However, organic liquid electrolytes may react exothermically and raise safety and environmental concerns. Solid-state batteries have emerged as an alternative to conventional lithium-ion batteries, due to their greater thermal stability, which can provide them with high safety and service life. However, there are still major challenges to overcome, such as low conductivity of lithium ions in solid electrolytes, scalable synthesis methods, and wide windows of electrochemical stability.
Among the different families of solid electrolytes, perovskite ceramic oxides such as Li3xLa2/3-xTiO₃ (LLTO) exhibit high grain ionic conductivities (> 1 mS/cm), but their total conductivities are two orders of magnitude lower. This work seeks to increase the total ionic conductivity by adding dopants such as Zr4+, Ta5+ and V5+ in the structure synthesized by the sol-gel method. The materials were characterized by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, electrochemical impedance, and galvanostatic charge-discharge curves.
All materials have a perovskite phase with a crystalline structure and space group P4/mm, and the dopants modify the TiO6 octahedral geometry, leading to changes in Ti–O bond distances and local structural distortion. Furthermore, the materials have vibrational modes typical of the ABO3 perovskite phase, low porosity, and relative densities greater than 95%, the 1% Zr-doped sample exhibited the highest total ionic conductivity (0.1 mS/cm), which can be associated with the more pronounced TiO6 octahedral distortion observed from the Ti–O bond lengths, and in the discharge-charge curves, the cells exhibited a coulombic efficiency of 90% after 10 cycles in lithium-ion batteries.

Metal hydrides are promising candidates for hydrogen storage due to their high volumetric hydrogen density. In this study, Sr₂H₄, a strontium-based hydride, is investigated using first-principles density functional theory (DFT) within the PBEsol generalized gradient approximation as implemented in CASTEP. The optimized structure exhibits a trigonal crystal system with lattice parameters a = b = 4.07 Å and c = 5.53 Å. Its negative formation energy confirms thermodynamic stability, while the absence of imaginary phonon modes indicates dynamical stability, mechanical stability is also ensured through the satisfaction of Born stability criteria. Electronic structure calculations reveal that Sr₂H₄ is a semiconductor with an indirect band gap of 1.109 eV, and optical analysis demonstrates favorable absorption and refractive properties, highlighting its potential for optoelectronic applications. From a hydrogen storage perspective, Sr₂H₄ shows a relatively high desorption temperature (~1008 K), a gravimetric capacity of 2.25 wt%, and a volumetric hydrogen density that meets U.S. Department of Energy targets. To improve its performance, strain engineering is applied, and the results indicate that compressive strain effectively weakens the Sr–H bonds and significantly reduces the desorption temperature, enabling hydrogen release near room temperature. These findings provide valuable insights into the design of efficient hydrogen storage materials and highlight the role of strain engineering as a practical strategy to optimize their performance under near-ambient conditions.

Due to the growing concern over global warming, significant efforts are being directed toward the production of green fuels obtained via the hydrogenation of captured CO₂ using hydrogen from renewable sources. Methane represents one of the most relevant e-fuels and can be produced through the Sabatier reaction. Among the various catalytic systems, Ni-based catalysts are widely investigated due to their high activity, good selectivity at relatively low temperatures, and lower cost compared to noble metal-based alternatives. Their performance is often enhanced by the presence of supports or promoters such as CeO₂.

In this work, composite catalysts consisting of a NiO active phase dispersed on mesoporous CeO₂ were developed. The mesoporous structure enables a high dispersion of NiO as ultra-small nanoparticles, improving catalytic efficiency while minimizing the amount of active phase.

NiO was deposited on the support using both impregnation and self-combustion methods, yielding catalysts with Ni loadings of 5, 10, and 15 wt%. XRD analysis indicates that NiO is highly dispersed, particularly at low loading, where no distinct crystalline phases are detected. This is supported by HR-TEM, EDX/EELS mapping, H₂-TPR, and H₂ chemisorption, confirming increased dispersion at lower Ni content.

Catalytic tests reveal high CO₂ conversion (80–85 mol%) for CeO₂-supported samples with near-complete CH₄ selectivity. Notably, catalytic activity is only weakly dependent on Ni loading, highlighting that a low Ni content (5 wt%) is sufficient to achieve high performance due to an improved dispersion. This is particularly relevant for reducing the use of Ni, a critical and potentially hazardous material, without compromising efficiency.