A bulk beta-BaB2O4 crystal was grown from a novel BaB2O4-NaBaBO3-BaMoO4 ternary solvent system with an optimal solvent composition using top-seeded solution growth (TSSG) and its optical properties were compared to those of a reference crystal grown from the conventional binary BaB2O4-NaBaBO3 system. The linear absorption spectrum was measured for both polarizations over an exceptionally broad range from ultraviolet (UV) to terahertz (THz) range (0.2-1500 mu m), revealing high transparency and low absorption coefficients, indicative of excellent material uniformity and purity. Nonlinear optical (NLO) performance was evaluated via secondharmonic generation (SHG) at 266 nm, showing comparable efficiency to the reference sample. These results demonstrate that the ternary system enables scalable crystal growth with preserved high optical quality, making it a promising candidate for industrial production of nonlinear optical elements.

Transition metal oxides are attractive alternative to noble metals in catalysts for CO removal in virtue of their activity and low cost, but their catalytic performance is significantly degraded in the presence of water. In this work, we demonstrate functional properties of delafossite Ag2CuMnO4-based systems including CO oxidation activity at room temperature under moisture-rich condition. It was established that the variation of the metal ratios during the synthesis of Ag2CuMnO4 does not substantially affect catalytic properties in dry CO oxidation. However, in the presence of water, only oxides with excess silver content proved to be catalytically active for the CO oxidation reaction. The excess silver, localized on the surface of Ag2CuMnO4 particles, was found to involve active oxide-like oxygen on sub-interface boundary promoting wet room-temperature CO oxidation. This process was proposed to proceed via the Mars-van Krevelen mechanism with the participation of active interface oxygen and its recovery through diffusion of the lattice mobile oxygen within delafossite structure. This work provides a good basis for further search and development of active water-resistant catalysts containing relatively inexpensive silver in comparison with Au-, Pd-, Pt-based materials.

Heterostructure photocatalysts attract a lot of attention of researchers thanks to their enhanced photocatalytic performance. Herein, we focus on the formation of the p-n type heterojunction based on bismuth metasilicate Bi2SiO5 and (3-Bi2O3. To date, there are some publications dedicated to these objects, however, the monitoring of the phase composition in the Bi2O3-Bi2SiO5 system and strong evidence of the heterostructure formation in the composite material have not been provided together. At first, we show with quantum-chemical calculations that such interface is possible to design. After that, using XRD in situ we clearly show the pathway of formation of Bi2SiO5 by consuming (3-Bi2O3 phase with increasing of temperature. Such results allow monitoring the phase content of the composite material. Finally, we choose two calcination modes to prepare the samples. Based on the results of HRTEM, DRS, XRD, IR and Raman data we clearly show the difference between the mechanical mixture of the semiconductors and generated heterostructure material. Photocatalytic properties of the samples are tested in photodegradation of Rhodamine B under different wavelength of LEDS. Under visible light (470 nm) the heterostructure demonstrates better catalytic activity. Additionally, using air flow and trapping agents it is demonstrated that the holes h+ mainly take part in deethylation of the dye.

Advances in the development of photocatalytic hydrogen production are determined by the creation of technologies to synthesize highly active catalysts. In this work, a simple and effective approach to increasing the activity of defective dark TiO 2 in photocatalytic hydrogen evolution reaction (HER) is implemented, based on self‐dispersing of (CuO x ) n over the titania surface. The use of aggregated (CuO x ) n clusters obtained by pulsed laser ablation, the presence of oxygen‐deficient Ti 3+ states in dark TiO 2 playing the role of an “anchor” to fix CuO x clusters, and the presence of surface Ti 4+ –OH groups facilitating the production of atomically dispersed Cu species allow achieving high performance. The conditions of interaction between dark TiO 2 and (CuO x ) n from simple mechanical mixtures to samples obtained by impregnation determine the state and dispersing of Cu‐containing species on the catalyst surface and photocatalytic properties. The catalysts are studied by XRD, TEM, XPS, and UV–vis spectroscopy. The dispersing efficiency of (CuO x ) n on the dark TiO 2 surface correlates with the increase in the AQY in photocatalytic HER. The maximum AQY of H 2 in a water‐glycerol mixture under LED irradiation (λ = 375 nm) is 55.3%, which is comparable to the best results for the (CuO x ) n ‐TiO 2 catalysts.

Recently, the urgency of combating antibiotic-resistant bacteria, viruses, and other pathogens has dramatically increased. With the development of nanotechnology, significant hopes are placed on nanoparticles with antimicrobial properties. The efficiency of such materials can be significantly enhanced through light-activated processes. In this study, we prepared composite ZnO-Ag nanoparticles and tested their ability to inhibit Staphylococcus aureus bacteria. The composite ZnO-Ag nanoparticles were fabricated using pulsed laser ablation of Zn and Ag targets in water using a nanosecond pulsed laser. During antibacterial tests, light-enhanced activation of the nanoparticles was achieved using low-power near UV (375 nm) and blue visible (410 nm) LED irradiation. For comparison, similar laser-fabricated ZnO nanoparticles were also tested. The combined use of nanoparticles and LED irradiation significantly increased the generation of reactive oxygen species. As a result, low nanoparticle concentrations (0.05 g/L) and low-power LED irradiation (0.17-0.22 W) significantly reduced the concentration of Staphylococcus aureus bacteria, including experiments with visible light irradiation. Compared to their ZnO counterparts, the use of ZnO-Ag composite particles led to an additional increase in antimicrobial activity.

The influence of structural defects in TiO2-based photocatalysts, prepared by pulsed laser ablation (Nd:YAG laser: λ 1064 nm, 180 mJ, 7 ns, 20 Hz) followed by thermal treatment in He and air, on the photocatalytic hydrogen evolution was studied. The phase composition and optical properties of the samples were determined by X-ray diffraction, Raman spectroscopy, and diffuse reflectance spectroscopy at all stages of preparation and processing. Photostimulation of dark TiOx samples revealed the appearance of absorption associated with the presence of oxygen vacancies (VO)/Ti3+ ions. A temperature-programmed oxidation (TPO) study of the sample surface in a flow of 10

Bimetallic Au–Pt nanoparticles with different molar ratios were obtained using laser synthesis (Nd:YAG laser with the parameters: 1064 nm, 180 mJ, 7 ns, and 20 Hz). The bimetallic nature of the particles was confirmed by X-ray diffraction and UV-visible spectroscopy. According to the transmission electron microscopy data, it was found that the bimetallic nanoparticles were represented by the alloy particles of an elongated shape with a diameter of 5–10 nm. Then, the bimetallic particles were decorated with a powder of highly defective dark titania by impregnation.The photocatalytic activity of the TiO2 with deposited bimetallic particles was estimated in the reactions of Rhodamine B dye decomposition and hydrogen production under LED irradiation with a wavelength of 375 nm. It was found that the highest photocatalytic activity in the series was exhibited by the samples with the deposited bimetallic particles, where the Au : Pt ratios was 50 : 50 and 30 : 70. It was also shown that the TiO2 nanoparticles decorated with the bimetallic Au : Pt NPs exhibited higher activity compared to the samples successively modified with monometals in the same ratios.

Purposeful synthesis of bismuth oxide nanoparticles (NPs) of various crystal modifications is important for biomedicine, photocatalysis and other applications. In this work, pulsed laser ablation of a metallic Bi target in atmospheric air is used to obtain (3- Bi 2 O 3 NPs. The effect of the Nd:YAG laser radiation power density (1064 nm, 7 ns) in the range of 0.1-1.2 GW/cm2 2 on the features of formation of NPs under nonequilibrium conditions is studied, for which the spectra of laser-induced plasma are recorded and analyzed, the plasma composition is determined, and the temperature of the plasma plume is estimated. The NPs are comprehensively characterized using TEM, XRD, FTIR, Raman, and UV-Vis spectroscopies, and electrophoretic light scattering, which make it possible to determine their morphology, crystal structure, chemical composition, and optical properties. The photocatalytic activity of the resulting nanopowders in the Rhodamine B dye decomposition reaction is assessed.

Improving the efficiency of photocatalysts for hydrogen production while minimizing the amount of noble metals used is a pressing issue in modern green energy. This study examines the effect of ultra-small Pt additives on increasing the efficiency of the CuOx-dark TiO2 photocatalyst used in the hydrogen evolution reaction (HER). Initially, Pt was photoreduced from the hydroxonitrate complex (Me4N)2[Pt2(OH)2(NO3)8] onto the surface of nanodispersed CuOx powder obtained by pulsed laser ablation. Then, the obtained Pt-CuOx particles were dispersed on the surface of highly defective dark TiO2, so that the mass content of Pt in the samples varied in the range from 1.25 × 10−5 to 10−4. The prepared samples were examined using HRTEM, XRD, XPS, and UV-Vis DRS methods. It has been established that in the Pt-CuOx particles, platinum is mainly present in the form of single atoms (SAs), both as Pt2+ (predominantly) and Pt4+ species, which should facilitate electron transfer and contribute to the manifestation of the strong metal–support interaction (SMSI) effect between SA Ptn+ and CuOx. In turn, in the Pt-CuOx-dark TiO2 samples, surface defects (Ov) and surface OH groups on dark TiO2 particles act as “anchors”, promoting the spontaneous dispersion of CuOx in the form of sub-nanometer clusters with the reduction of Cu2+ to Cu1+ when localized near such Ov defects. During photocatalytic HER in aqueous glycerol solutions, irradiation was found to initiate a large number of catalytically active Pt0-CuOx-Ov-dark TiO2 centers, where the SMSI effect causes electron transfer from titania to SA Pt, thus promoting better separation of photogenerated charges. As a result, ultra-small additives of Pt led to up to a 1.34-fold increase in the amount of released hydrogen, while the maximum apparent quantum yield (AQY) reached 65%.

The article presents the results of investigation of the morphology and elemental composition of refractory metals multioxide particles synthesized under conditions of laser ablation of a high-entropy alloy. The alloy was obtained by spark plasma sintering of an equiatomic mixture of powders (W–Ta–Mo–Nb–V–Zr–Cr–Ti) after preliminary high-energy ball milling. It was found that the multioxide particles formed under conditions of laser ablation with sizes from 20 to 80 nm have a spherical or quasi-spherical shape and are characterized by an almost uniform volume distribution of oxygen and refractory elements. The results of transmission electron microscopy and X-ray diffraction analysis indicate an amorphous-crystalline structural state of the multioxide particles. After annealing at a temperature of 700 °C, the particles, while maintaining nanoscale sizes, acquire a nonequiaxed shape with partial faceting. With the complex use of structural investigation methods, it was found that almost the entire volume of the powder mixture transforms into a crystalline phase characterized by a tetragonal lattice. Low-angle fragmentation boundaries and areas with high crystal lattice curvature were found inside the particles. It is assumed that residual local stresses are a consequence of local imperfection of the crystal lattice (dilations and distortions due to differences in the sizes of atoms), which can be represented as partial disclinations and their configurations.

A new laser vaporization (LAVA) method for the synthesis of CeO 2 nanoparticles, allowed the synthesis of support samples with widely variable surface area and particle sizes. The LAVA‐synthesized CeO 2 nanoparticles exhibit a high degree of crystallinity, characterized by the absence of intracrystalline porosity, but high surface defectiveness and a well‐developed interblock structure. Platinum deposition produces highly dispersed species, including isolated ions (single atoms Pt 2+ ‐SA), ion associates (2D‐PtO x rafts), and oxidized 3D‐PtO x clusters. The catalyst with the largest surface area and the smallest mean particle size of CeO 2 contains platinum mainly in the Pt 2+ ‐SA form, owing to its strongest chemical interaction with the surface of small‐sized nanoparticles. This highly dispersed catalyst does not exhibit low‐temperature activity in CO oxidation, since ignition of the reaction is only observed at T > 150 °C. The catalysts with reduced surface area contain both Pt 2+ ‐SA and 3D‐PtO x clusters located at extended surface defects and along interblock boundaries. The formation of 3D‐PtO x cluster species results in a significant enhancement of the catalytic activity. The most notable catalytic effect is observed for the lowest surface area catalysts, for which CO conversion shows low‐temperature activity with the reaction ignition occurring at sub‐zero temperatures.

Cu-containing and Ce-modified OMS-2 catalysts were prepared at various calcination temperatures using the hydrothermal method and tested for low-temperature CO oxidation. The structure, chemical compositions, and physical–chemical properties of the catalysts were characterized using XRD, N2 physisorption, XRF, Raman spectroscopy, SEM, high-resolution TEM with EDX, TPR-H2, and XPS. The incorporation of Cu into the Ce-OMS-2 sample facilitated the transformation of pyrolusite into cryptomelane, as confirmed by Raman spectroscopy data. In the light-off mode, the Cu/Ce-OMS-2-300 and Cu/OMS-2 samples exhibited higher activity in low-temperature CO oxidation (T90 = 115 and 121 °C, respectively) compared to sample Cu/Ce-OMS-2-450. After a long-run stability test, the Cu/Ce-OMS-X samples demonstrated excellent performance: the T80 increased by 16% and 7% for the samples calcined at 300 °C and 450 °C, respectively, while the T80 for the Cu/OMS-2 increased by 40%. The Cu/OMS-2 and Cu/Ce-OMS-2-300 samples were found to have an increased content of nanodispersed copper sites on their surfaces. These copper sites contributed to the formation of the Cu2+-O-Mn4+ interface, which is responsible for the CO oxidation. The presence of Ce3+ in the catalyst was found to increase its stability in the presence of water vapor due to the higher reoxidation ability in comparison with Ce-free sample Cu/OMS-2.

The need to develop a surgical instrument that can most effectively and minimally invasively remove a malignant tumor, and distinguish and destroy only tumor cells without damaging the normal cells of healthy tissue surrounding the tumor is being considered. To achieve this goal, it is proposed to use nanodiscs with special magnetic, electronic and optical properties. Nanodiscs modified with recognition ligands (aptamers) are able to bind to tumor cells and destroy them under the influence of a weak, nonheating alternating magnetic field. This allows for effective tumor destruction while minimizing the impact on surrounding healthy tissue.

Photocatalysis offers a powerful approach for water purification from toxic organics, hydrogen production, biosolids processing, and the conversion of CO2 into useful products. Further advancements in photocatalytic technologies depend on the development of novel, highly efficient catalysts and optimized synthesis methods. This study aimed to develop a laser synthesis technique for bismuth oxyhalide nanoparticles (NPs) as efficient and multifunctional photocatalysts. Laser ablation of a Bi target in a solution containing halogen salt precursors, followed by laser plasma treatment of the resulting colloid, yielded crystalline bismuth oxyhalides (BixOyXz, where X = Cl, Br, or I) NPs without the need for additional annealing. The composition, structure, morphology, and optical properties of the synthesized BixOyXz (X = Cl, Br, I) NPs were characterized using XRD analysis, electron microscopy, Raman spectroscopy, and UV-Vis spectroscopy. The effect of the halogen on the photocatalytic activity of the double oxides was investigated. The materials exhibited high photocatalytic activity in the degradation of persistent model pollutants like Rhodamine B, tetracycline, and phenol. Furthermore, the BixOyXz NPs demonstrated good efficiency and high yield in the selective oxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-furandicarboxylic acid (FDCA). The obtained results highlight the promising potential of this laser synthesis approach for producing high-performance bismuth oxyhalide photocatalysts.

The optical properties of new three-cation crystals family RE x Nd y Sc z (BO3)4 (RE:NSB), where RE are Sm - Lu lanthanides and x + y + z = 4, have been studied. The influence of the cation RE on the absorption and luminescence spectra of crystals was determined. The effective nonlinearity coefficient of crystals for second harmonic generation (SHG) of Nd:YAG laser radiation (1064 nm, 7 ns) was estimated using the Kurtz-Perry powder method. It is established that for the RE:NSB series, the highest luminescence intensity and SHG efficiency is demonstrated by the Gd:NSB crystal. It may be promising as active medium of self-frequency doubling solid-state lasers.

A wide range of solid solutions based on TbBO3 (with ScBO3 ≤ 30 mol%) and ScBO3 (with TbBO3 ≤ 50 mol%) was found in the TbBO3–ScBO3 system. Under UV excitation the characteristic green emission is visible due to the typical 5D4–7F5 transition of Tb3+. The intensity of photoluminescence significantly depends on the doping concentration of Tb3+ and the optimal concentration has been determined as x = 0.05. Crucial impact of hydrogen treatment on the luminescent properties was found. The compositions of TbxSc1–xBO3 (x = 0.05–0.1), after being treated with hydrogen at a temperature of 800 °C, has high potential for practical application as a green phosphor. This is due to its impressive quantum yield value of up to 69 % when excited by a 378 nm.

A combination of laser ablation and laser irradiation by focused laser beam in liquid is used to prepare the Bi-and Si-based nanocolloids in water in a Bi:Si molar ratio of 12:1. The composition, structure, morphology, and optical properties of the obtained nanostructures are studied. The synthesized composite nanostructures are shown to consist mainly of bismuth oxycarbonate Bi2(CO3)O2 and bismuth silicate Bi12SiO20. The materials are tested in the decomposition of the model dye rhodamine B, including the stability of the catalyst and the opportunity of its regeneration by laser irradiation as well as in phenol decomposition when excited by LED with a wavelength of 375 nm. The opportunity to use the Bi-Si-based colloidal nanostructures for the selective photooxidation of 5-(hydroxymethyl)furfural is considered.

Solid solutions based on (Eu,Gd)Sc3(BO3)4 , Gd)Sc 3 (BO 3 ) 4 (C2/c) and Gd 0.25 Sc 0.75 BO 3 (R R 3) in the EuSc3(BO3)4-GdSc3(BO3)4 3 (BO 3 ) 4-GdSc 3 (BO 3 ) 4 system were studied. Synthesis at 1250 degrees C provides wide homogeneity regions which are stable at room temperature. Melt-solution crystallization of both compounds from LiBO2-LiF 2-LiF flux was shown. All the obtained samples have luminescence characteristic of Eu3+ 3+ with a largest peak at 615 nm corresponding to the 5 D 0 -> 7 F 2 transition. In this series the luminescence intensity monotonically increases with an increase of Eu content. The largest quantum yield of luminescence (53 %) in the EuSc3(BO3)4-GdSc3(BO3)4 3 (BO 3 ) 4-GdSc 3 (BO 3 ) 4 system is demonstrated by EuSc3(BO3)4 3 (BO 3 ) 4 sample.

In the present work, the highly effective nanoscale Cu-modified dark TiO2 photocatalysts for hydrogen evolution reactions are prepared by pulsed laser ablation with and without additional laser treatment (ALT). Transmission electron microscopy HR results show that copper is distributed along the dark titania surface both in the form of subnanometer oxide clusters and single atoms (SAs). After the ALT, the Cu dispersion increases, and a large number of SAs appear. The X-ray photoelectron spectroscopy data indicate that the increasing copper content as well as the ALT lead to an increase in the surface Ti3+ content. Copper on the surface exists in the Cu+ state, which is associated with the strong metal-support interaction (SMSI) effect between the defective TiO2 support and a SA/subnanometer cluster of copper. Photocatalytic activity of nanoscale Cu-modified dark TiO2 is studied in the hydrogen evolution from aqueous glycerol solution under irradiation with light-emitting diodes (LEDs) 375 (soft ultraviolet) and LED 410 (visible region). In all cases, the modification of the surface with copper significantly increases the hydrogen yield in both the UV and visible regions. The ALT also leads to an increase in the photocatalytic activity of materials due to an increase in the SMSI between copper species and the surface of the dark TiO2. For the process of photocatalytic hydrogen evolution, a mechanism is proposed, and the products of glycerol photooxidation are identified.

The phase diagram of the Sr3B2O6-NdBO3 binary system was studied. The intermediate compound Sr3Nd2(BO3)(4) can be synthesized over a wide range of compositions, from 27 to 70 mol.% NdBO3 , at 1200(degrees)C The maximum luminescence of Nd in this solid solution was measured for the highest content of Sr. The partial substitution of Nd by 3 mol.% Sr in NdBO3 does not significantly affect the presence of concentration quenching. The phase exhibiting the strongest luminescence within the system is neodymium doped Sr(3)B2O(6).