Introduction.

An important reaction contributing to the development of hydrogen energy and the potential replacement of the Haber–Bosch industrial process for ammonia synthesis is the electrocatalytic nitrogen reduction reaction, as well as the key reactions for optimizing this latter reaction: electrocatalytic nitrate and nitrite reduction reactions. Due to nitrate contamination of agricultural and industrial wastewater, nitrite contamination can be more dangerous due to the greater toxicity of the nitrite ion. Thus, the search for efficient and low-cost catalysts based on non-precious metals and their compositions is currently crucial. In turn, intermetallic compounds (IMCs) are currently poorly studied for this purpose and, at the same time, are in demand, since their catalytic efficiency can potentially approach single atomic catalysts (SACs). The aim of our study is to synthesize IMCs based on Ge and transition metals and test catalysts based on this in the electrochemical nitrite reduction reaction (NO₂^–RR).

Methods.

The Ge-IMC samples were prepared using arc melting in an argon atmosphere at the AM-200 facility. Mass control of the samples after fusion showed that melting losses did not exceed 1 mass%. The physicochemical methods of characterization of Ge-IMC samples were used in the work: UV-vis spectroscopy and XRD. Linear voltammetry and chronoamperometry were used to determine the optimal conditions for the reactions and synthesis of ammonia, respectively. Autolab PGSTAT302N and PS-20 potentiostats were also used.

Results and Discussion.

The results show that the use of Ge electrocatalysts is promising, since excellent values of Faradaic efficiency (FE) and ammonia yield rate were achieved in the NO₂^–RR . Moreover, IMC-based catalysts showed good results at significantly lower potentials than solid solution catalysts.

Acknowledgment.

The research was carried out at the expense of the grant of Russian Science Foundation (RSF) No 25-29-00488, https://rscf.ru/en/project/25-29-00488/.

The increasing consumption of pharmaceuticals and their continuous release into aquatic environments have raised significant environmental concerns. Even at low concentrations, these contaminants can negatively impact ecosystems and human health. Conventional wastewater treatment plants (WWTPs) are often insufficient for their complete removal, emphasizing the need for more advanced treatment solutions. Among advanced oxidation processes (AOPs), heterogeneous photocatalysis has shown promise for the efficient degradation of various pharmaceutical compounds, including antibiotics, analgesics, anti-inflammatory drugs, and anesthetics. Graphitic carbon nitride (g-C₃N₄), a polymeric, metal-free semiconductor composed primarily of carbon and nitrogen, is a promising material for visible-light-driven photocatalysis. In this study, g-C₃N₄ was synthesized via thermal polymerization using urea and melamine as nitrogen-rich precursors. The materials were subsequently exfoliated to improve their surface area and enhance photocatalytic activity. The prepared samples were characterized using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) to determine bonding environments and crystal structure. Brunauer–Emmett–Teller (BET) surface area analysis was used to evaluate textural properties, and diffuse reflectance spectroscopy (DRS) was employed to estimate the optical band gap. The adsorption behavior and photocatalytic degradation of procaine, a local anesthetic, were studied under UV-A light and simulated solar irradiation in a batch reactor. Preliminary results suggest that exfoliated g-C₃N₄ synthesized from urea exhibits improved photocatalytic performance compared to other variants, likely due to its higher surface area. While full comparative testing is ongoing, these findings indicate that urea-derived, exfoliated g-C₃N₄ is a promising candidate for solar-driven degradation of pharmaceutical pollutants.

Capturing CO₂ from the atmosphere represents a key challenge, since CO₂ has been recognized as the primary anthropogenic greenhouse contributor to the increase in Earth’s average temperature. Their high porosity, tunable pore size and large surface area make Metal-Organic Frameworks (MOFs) promising candidates to uptake and separate CO₂ from gaseous mixtures. In 2021, some of us synthesized, via hydrothermal approach, a new microporous MOF, formulated as [Co(trz₂An)]n·2.5H₂O (CAMOF-1), by combining 3, 6-N-ditriazolyl-2,5-dihydroxy-1,4-benzoquinone, as organic linker, with a Co^II metal node in a 1:1 stoichiometric ratio. This MOF showed a favourable balance of high selectivity, high adsorption capacity, and high regenerability, thus being a promising candidate for CO₂ gas separation processes. We report herein the synthesis, crystal structure and performance studies of three new microporous MOFs obtained by combining trz₂An with Cu^II, Zn^II and Fe^II metal nodes, formulated as [Cu(trz₂An)]^.nH₂O (CAMOF-2), Zn(Trz₂An)^.3H₂O (CAMOF-3) and Fe(Trz₂An)^. 3H₂O (CAMOF-4). CAMOF-2-4 show a 3D robust structure, with a pore size of 3.46 Å for CAMOF-2 and 3,89 Å for CAMOF-3,4, consistent with the kinetic radius of CO₂ and absorption capacity of 2 molecules of CO₂ / unit formula as confirmed by pore analysis data. Static and Dynamic Adsorption Measurements revealed i) remarkable carbon dioxide uptake, ii) high selectivity in CO₂:N₂ gas mixtures, iii) easy regeneration in mild conditions. Furthermore, i) preliminary CO₂ electroreduction studies showed a good capability of CAMOF-2 to convert carbon dioxide into ethylene and ii) adsorption test removal, performed on CAMOF-3 and CAMOF-4, revealed a good performance inremoving Cd^II, at different pH ranges and concentrations. In conclusion, trz₂An is a strategic organic linker, which combined with different transition metal ions, gave rise to a novel thermal stable, robust, microporous 3D MOFs family employing for environmental quality.

The band gap energy in semiconducting materials is crucial for electric structure and is needed for procedures like water splitting. Electrostatic coalescence is an effective method for separating water from crude oil in the petroleum industry. Electrode geometry plays a crucial role in electrocoalescence, the process of phase separation in emulsions using electric fields. It influences the distribution of the electric field applied to the emulsion, affecting coalescence efficiency. The shape and size of electrodes can also affect the electric field strength at different points in the emulsion, promoting more efficient droplet coalescence.

Electrode geometry can also influence the direction of droplet flow in the emulsion, optimizing the phase separation process. Proper geometry can minimize unwanted side effects, such as the formation of more stable emulsions or undesirable electrochemical reactions. The choice of electrode geometry can be optimized for different types of emulsions and operating conditions, improving the efficiency of the electrocoalescence process.

This study investigates the influence of electrode geometry on electrocoalescence, a process that uses electric fields to separate phases in emulsions, focusing on oil–water separation. Electrodes coated with metal oxides (TiO2, Nb2O5, and Al2O3) were designed for a static electrocoalescence cell. The optical and structural properties of the oxides were analyzed by X-ray diffraction and UV-Vis spectroscopy. The results show that the metal oxides have different band gap energies, which can be adjusted to optimize the electrocoalescence process. The indirect and direct band gap energies were determined for each oxide: TiO2 (3.18 eV and 2.96 eV), Al2O3 (4.29 eV and 3.67 eV/2.60 eV), and Nb2O5 (3.54 eV and 2.90 eV).

Introduction

Bismuth-based perovskite materials have emerged as promising candidates for gamma ray detection due to their high atomic number, tunable optoelectronic properties, high bandgap, and cost-effective synthesis. This study investigates the structural, optical, and radiation detection properties of a (CH₃NH₃)₃Bi₂Cl₉ (MABiCl) perovskite material in pelletized form.

Methods

Synthesis of the lead-free Bi-based perovskite MABiCl material as a light absorber was performed by mixing a 3:2 M ratio of CH₃NH₃Cl and BiCl₃ at 50^◦C in DMF. The solution was stirred for half an hour, resulting in a white foggy solution. In total, 20 ml ethyl alcohol was added to achieve a white precipitate. The solution was filtered and dried under a constant temperature of 60^◦C under vacuum conditions to obtain MABiCl powder.

Results

X-ray diffraction (XRD) analysis confirms the formation of a highly crystalline perovskite structure with well-defined peaks, indicating phase purity. UV-Vis spectroscopy reveals a bandgap of 2.4 eV, which is suitable for efficient charge carrier generation under gamma ray exposure. Temperature-dependent electrical study, conducted at both high and low temperatures, demonstrate the material’s thermal stability and consistent performance across a wide temperature range, making it viable for diverse operational environments. Current versus time measurements under gamma ray irradiation from various sources (Co⁶⁰, Cs¹³⁷, Na²⁴) exhibit a rapid and reproducible photo response, with high sensitivity and low noise, indicating effective charge collection and detection efficiency. The material’s response to gamma rays shows a linear correlation between current output and radiation dose, highlighting its potential for quantitative detection applications.

Conclusion

These findings suggest that the Bi-based perovskite material possesses favourable properties for gamma ray detection, including structural robustness, suitable optical characteristics, and reliable radiation response. Further optimization of material composition and device fabrication could enhance detection efficiency and scalability, paving the way for practical applications in medical imaging, nuclear security, and radiation monitoring.

Introduction
Nowadays, research is increasingly focusing on green fuels produced from captured CO₂ (e-fuels). One of the most promising candidates is dimethyl ether (DME), a substitute for diesel fuel. DME can be synthesized from CO₂ via two consecutive reactions: the first, catalyzed by Cu-based reduction catalysts, involves the reduction of CO₂ to methanol; the second, promoted by solid acid catalysts, is the dehydration of methanol to DME. In this work, three mesostructured aluminosilicates (Al-SBA-16) with three different Si/Al ratios (10, 15, and 20) are presented as methanol dehydration catalysts for the one pot-CO₂-to-DME conversion. The catalysts have been tested and characterized with a particular focus on the correlation of their structural properties with their acid features and their catalytic performance.

Methods
The Al-SBA-16 samples were obtained with an Evaporation-Induced Self-Assembly (EISA) method using a silicon alkoxide (TEOS) and aluminum chloride as precursors. The samples were studied with a wide range of techniques to determine their structural, textural, morphological, and acid properties, and evaluated to determine their catalytic performance.

Results and discussion
Catalytic tests reveal an increased activity with higher Al content, in agreement with pyridine-FTIR acid site characterization, which shows a moderate increase in acid site number with decreasing Si/Al ratios; however, the trend is less pronounced than expected based merely on the Si/Al ratio. To investigate this finding, ²⁷Al and ²⁹Si solid-state NMR were employed to gather molecular-level insights into the structure–acidity relationship. The ²⁷Al-SS-NMR spectra reveal the presence of both tetrahedral (framework and Al₂O₃-derived) and octahedral Al species. A higher Si/Al ratio enhances aluminum incorporation into the framework, while higher aluminum content favors the formation of extra-framework Al₂O₃. These findings highlight the critical role of Al coordination and distribution in tuning acidity and catalytic activity.

Introduction

The increasing demand for sustainable and environmentally friendly construction materials has spurred interest in biopolymer composites reinforced with agricultural waste. Rice husk (RH), a byproduct of rice milling, is abundant and rich in lignocellulosic fibers and silica, making it an excellent for use in fiber-reinforced biopolymers. This study investigates recent developments in RH-reinforced biopolymer composites and evaluates their potential in construction applications due to their mechanical, thermal, and ecological advantages.

Methods

Rice husk was subjected to alkaline treatment using 5% NaOH to remove surface impurities and enhance fiber–matrix interaction. The treated fibers were incorporated into various polymer matrices including low-density polyethylene (LDPE), polylactic acid (PLA), epoxy resin, and unsaturated polyester. The composites were fabricated through melt blending and compression molding techniques. Physical and mechanical properties—such as tensile strength, flexural strength, impact resistance, water absorption, and thermal stability—were measured according to ASTM standards.

Results

Incorporation of RH improved mechanical performance in all tested polymers. LDPE/RH composites exhibited a 25% increase in tensile strength (from 13.2 MPa to 16.5 MPa), while epoxy/RH systems showed a 32% enhancement in flexural strength. Treated composites exhibited an 18% increase in hardness. RH ash increased compressive strength of cementitious composites by 15%. In biodegradability studies, composites with RH particles <250 μm showed 60% degradation after 90 days. RH biochar and chitosan-enhanced soil samples showed a 22% increase in shear strength.

Conclusions

Fiber-reinforced biopolymers made from rice husk waste show significant promise as sustainable alternatives to conventional construction materials. Their enhanced mechanical properties, biodegradability, and thermal performance make them suitable for use in panels, insulation, cementitious composites, and soil reinforcement. These materials contribute to circular economy practices and offer environmentally friendly solutions for green construction. Further research should focus on large-scale implementation, cost analysis, and long-term durability studies.

The integration of ferroelectric nematic liquid crystals (FNLCs) into polymer matrices offers a promising route to enhance dielectric and ferroelectric properties of the composites and thus improve the surface charge generation, which can be exploited to explore the triboelectric energy harvesting application. In this study, we report the development of an advanced poly(vinylidene fluoride) (PVDF)-based composite self-supporting film by infusing a novel room-temperature FNLC (FNLC-1571) for high-performance triboelectric nanogenerators (TENGs). The composites were prepared via the spin coating method to achieve a uniform thickness (~100 μm) and controlled surface morphology. Incorporation of FNLCs within the PVDF matrix induced intermolecular nucleation, promoting enhanced crystallinity and preferential formation of the electroactive β-phase, as confirmed in related literature on LC-polymer composites. The presence of FNLC molecules, with their long-range polar order and high dielectric anisotropy, facilitates efficient dipole alignment and increases the net dielectric permittivity, thereby improving charge density during triboelectric contact. The fabricated films functioned as tribo-negative layers in a vertical contact–separation-mode TENG, paired with aluminum (Al) as the tribo-positive counterpart. The optimized device delivered an open-circuit voltage of ~60 V_PP and a short-circuit current (I_SC) of ~5 µA under low mechanical excitation (~10N force @ 15Hz), demonstrating high sensitivity to small-amplitude vibrations. The enhancement in triboelectric output is attributed to the synergistic effect of increased β-phase content, improved interfacial polarization, and optimized device geometry, which maximized effective contact area and charge transfer efficiency. This work establishes FNLC-infused PVDF composites as a viable and scalable material platform for next-generation self-powered sensors, portable electronics, and IoT-compatible energy harvesting systems.

The innovative design and development of bifunctional electrocatalysts that exhibit both high catalytic activity and enhanced stability for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are both highly desirable and challenging objectives. Transition metal phosphides (TMPs) are recognized as highly effective electrocatalysts due to their abundance of active surface sites, excellent electrical conductivity, and strong chemical stability. These characteristics are derived from the intrinsic high electrocatalytic activity of the metal (M) centers and phosphorus (P) sites. In this study, cobalt phosphide (CoP) and cobalt–iron phosphide (CoFeP) were directly deposited on copper (Cu) substrates via an electroless deposition method. The P source and reducing agent used in this process was sodium hypophosphite (NaH₂PO₂). Gold (Au) nanoparticles were subsequently anchored to the phosphides through a galvanic displacement strategy, thereby creating a composite material with enhanced properties. A comprehensive investigation was conducted to elucidate the morphology, composition, and crystal structure of the catalysts. This investigation utilized a range of analytical techniques, including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The electrocatalytic bifunctionality of the materials for overall water splitting (OWS) was evaluated in a two-electrode setup in a 1 M KOH electrolyte.

The Au-CoFeP catalyst demonstrated notable bifunctional activity, achieving a low cell voltage of 1.68 V at 10 mA cm^-2. This performance was superior to that of the Au-CoP catalyst, due to synergy among the Co, Fe, and Au elements. The combination of the Au modification and bimetallic CoFeP composition led to lower overpotentials and enhanced stability, underscoring a practical and effective strategy for designing gold-modified transition metal phosphides as durable and efficient candidates for application in the field of electrocatalysis.

Acknowledgement

This research was funded by a grant (No. P-SV3-25-715) from the Research Council of Lithuania.

The performance parameter of Cu₂ZnSnS₄ (Copper Zinc Tin Sulphide) based heterostructure solar cell have been studied by one dimensional solar capacitance simulator software program (SCAPS 1D). This software provides device performance based on layer by layer material properties. The proposed device structure Mo/ Cu₂ZnSnS₄ / CdS / ZnO integrates the properties such as non toxic, cost effective, environmental friendly and photovoltaic making them suitable for photovoltaic applications. The key structural parameters such as thickness, carrier concentration and doping were systematically varied to analyze the effect on device performance. To enhance the cell power efficiency optimization of the device and their key parameters has been performed. The effect of changing doping concentration and thickness of electron transport layer (ETL) and hole transport layer (HTL) has also been studied. The simulation study includes the comprehensive analysis of J-V characteristics, recombination mechanism, carrier density profiles, Quantum efficiency and I-V behavior under AM 1.5 spectrum illumination at 300 K temperature. By tuning these parameters, the optimized device structure demonstrates a significant improvement in photovoltaic performance. The simulated device has achieved power conversion efficiency (PCE) of 21 %. The result indicates the potential of CdS as an effective buffer layer in Cu₂ZnSnS₄ based solar cell in achieving high efficiency and stable solar devices.