A unique method for synthesizing a surface modifier for metallic hydrogen permeable membranes based on non-classic bimetallic pentagonally structured Pd-Pt nanoparticles was developed. It was found that nanoparticles had unique hollow structures. This significantly reduced the cost of their production due to the economical use of metal. According to the results of electrochemical studies, a synthesized bimetallic Pd-Pt/Pd-Ag modifier showed excellent catalytic activity (up to 60.72 mA cm⁻²), long-term stability, and resistance to CO_ads poisoning in the alkaline oxidation reaction of methanol. The membrane with the pentagonally structured Pd-Pt/Pd-Ag modifier showed the highest hydrogen permeation flux density, up to 27.3 mmol s⁻¹ m⁻². The obtained hydrogen flux density was two times higher than that for membranes with a classic Pd_black/Pd-Ag modifier and an order of magnitude higher than that for an unmodified membrane. Since the rate of transcrystalline hydrogen transfer through a membrane increased, while the speed of transfer through defects remained unchanged, a one and a half times rise in selectivity of the developed Pd-Pt/Pd-Ag membranes was recorded, and it amounted to 3514. The achieved results were due to both the synergistic effect of the combination of Pd and Pt metals in the modifier composition and the large number of available catalytically active centers, which were present as a result of non-classic morphology with high-index facets. The specific faceting, defect structure, and unusual properties provide great opportunities for the application of nanoparticles in the areas of membrane reactors, electrocatalysis, and the petrochemical and hydrogen industries.

The magnesium nanosized ferrite powder with formula MgFe₂O₄ was synthesized via a pyrochemical sol–gel glycine–nitrate method and annealed consistently at temperatures of up to 1300 °C. The MgFe₂O₄ ferrite samples’ microstructure was studied by SEM and XRD methods. According to the results of the studies, the increase in MgFe₂O₄ nanoparticles size from about 15 nm to micron-sized particles was observed when increasing annealing temperatures. The DC electrical conductivity of MgFe₂O₄ also clearly shows the change in conduction behavior of samples with increased calcination temperatures. The electromagnetic microwave properties of micron-sized particles of MgFe₂O₄ ferrite powder for a 1200 °C annealing temperature were studied for composites in paraffin matrix with produced magnetic filler mass concentration at 40% and 50%. The filament composites of polymer polylactic acid with MgFe₂O₄ ferrite powder samples were prepared by the FDM 3D-printing process and their microwave-absorbing properties were investigated. The application of developed PLA–MgFe₂O₄ ferrite filament for fabricating magnetic microwave-absorbing components also was demonstrated.

The article presents the results of an investigation of composites based on manufactured samples of fiberglass metalized with a submicron film made of brass, neusilber and non-magnetic SS304 stainless steel. It was found that, due to their characteristics, the samples of metallized fiberglass are an effective electromagnetic wave-absorbing filler for various building and construction materials; The developed metallized fiberglass samples are also useful for the creation of EMI-shielding building materials for protection from microwave radiation. With an increase in the proportion of metalized glass fiber, the electromagnetic shielding of the studied composites increases systematically. It is determined that at a concentration of 5 wt.% brass-metallized glass fiber, a test composite material with a thickness of 250 mm is able to shield up to 13.7 and 21.2 dB in the 4G and 5G ranges of cellular communication electromagnetic waves, respectively.

A gadolinium stearate powder has been synthesized and its microstructure has been studied by scanning electron microscopy. The powder composition and proposed structure have been determined using IR spectroscopy, X-ray powder diffraction, and elemental analysis. Molecular modeling of the spatial chain structure of gadolinium stearate for the nine-coordinate central Gd(III) ion has been performed by the molecular mechanics method. The magnetic and dielectric properties of gadolinium stearate have been investigated by means of a vector network analyzer as a function of the frequency of the applied electromagnetic radiation.

In this study, cobalt-zinc ferrite (Co0.5Zn0.5Fe2O4) was obtained by the glycine-nitrate method followed by annealing in a high-temperature furnace at a temperature of 1300 °С. The qualitative composition and its microstructural characteristics were determined using energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, and scanning electron microscopy.The analysis of the micrographs demonstrated that the cobalt-zinc ferrite micropowder obtained after thermal annealing has an average particle size of 1.7±1 μm. The analysis of XRD data showed that the annealed cobalt-zinc ferrite micropowder has a cubic crystal structure with a lattice parameter of a = 8.415 Å. Using the Scherrer and Williamson-Hall equations we calculated the average sizes of the coherent scattering regions, which were commensurate with the size of crystallites: according to the Scherrer equation D = 28.26 nm and according to the Williamson-Hall equation D = 33.59 nm and the microstress value e = 5.62×10–4 in the ferrite structure.Using a vector network analyser, the electromagnetic properties of a composite material based on synthesized cobalt-zinc ferrite were determined. The frequency dependences of the magnetic and dielectric permeability values from the measured S-parameters of the composite material (50% ferrite filler by weight and 50% paraffin) were determined using the Nicolson-Ross-Weir method and were in the range of 0.015–7 GHz. The analysis of the graphs of the dependence of the magnetic permeability on the frequency of electromagnetic radiation revealed a resonance frequency of fr ≈ 2.3 GHz. 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A new coordination compound of gadolinium(III) with 2,5-dimethoxybenzoic acid was obtained via electrochemical synthesis. The composition of the coordination compound was investigated by means of C‒H analysis, X-ray spectral energy dispersive microanalysis, IR spectroscopy, and thermogravimetric analysis. The triplet level of 2,5-dimethoxybenzoic acid was determined from the luminescence spectra of the metal complex. The parameters of fine structure are determined using EPR spectra of the powder of the metal complex.