Search Results (1,412)

The development of efficient visible-light-driven semiconductor photocatalysts is essential for scalable and sustainable green hydrogen production. Among ternary metal oxides, MV₂O₆ (M = Zn, Ni, Cu, Mn, Co, etc.) metavanadates have attracted considerable interest because of their narrow band gaps (~1.8–2.5 eV), strong visible-light absorption, and unique edge-sharing VO₆ octahedral framework that promotes charge separation. This review summarizes recent advances in the design, synthesis, and electronic engineering of MV₂O₆-based photocatalysts for solar water splitting. Since direct particulate overall water splitting has only been demonstrated for MnV₂O₆, whereas ZnV₂O₆, NiV₂O₆, and CuV₂O₆ have mainly been investigated as photoelectrodes, both particulate photocatalytic and photoelectrochemical (PEC) systems are critically examined. The review clearly distinguishes these two configurations, highlighting how PEC studies provide valuable insights into charge transport, interfacial processes, and reaction kinetics while recognizing the additional challenges associated with suspension-based photocatalysis. Fundamental crystal structures, electronic band alignments, and charge-transfer characteristics of MV₂O₆ compounds are discussed, followed by recent advances in synthesis strategies, including hydrothermal, sol–gel, and deep eutectic solvent (DES)-assisted methods, together with morphology and defect engineering. Particular attention is given to oxygen-vacancy formation and its influence on visible-light absorption and charge separation. Modification strategies, including elemental doping, cocatalyst loading, and the construction of Z-scheme and step-scheme (S-scheme) heterojunctions, are critically evaluated for improving photocatalytic efficiency. Finally, the review discusses the key challenges that limit practical applications, including unfavorable band-edge positions, rapid carrier recombination, sluggish surface reaction kinetics, photostability, and the need to establish composition–structure–activity relationships. Future perspectives emphasize rational materials design through advanced characterization, theoretical calculations, and scalable synthesis approaches to accelerate the development of efficient MV₂O₆ photocatalysts for solar-driven hydrogen production. Full article

The Hailijin uranium (U) deposit is one of the super-large U-deposits recently discovered in the Qianjiadian ore field, southwestern Songliao Basin. The ore bodies are mainly hosted in the lower member sandstones of the Upper Cretaceous Yaojia Formation and occur as multilayered tabular bodies. The nature and source of the ore-forming fluids remain unclear, limiting the understanding of the genetic type of the deposit. This study integrated drill-core observation, mineralogy, whole-rock geochemistry, in situ pyrite trace elements and sulfur isotopes, fluid-inclusion, and Raman spectroscopy to constrain ore-forming fluids. The host sandstones experienced hematitization, limonitization, carbonate cementation, clay alteration, sulfidation and bleaching. Pitchblende and coffinite occur as submicron grains in dissolution pores of quartz and feldspar, on clay-mineral surfaces and within mobile organic matter (OM), commonly associated with pyrite and sphalerite. The ores and gray mineralized sandstones are enriched in U, Mo, Re, Co, Ni, Zn and Pb, and syn-ore pyrite shows positive correlations between U and As, Mo, Cu, Zn, Se and Sb. Mineralization-related fluid-inclusion assemblages occur mainly in syn-ore dolomite/ankerite cements and in secondary trails along microfractures in detrital quartz; they yield homogenization temperatures of 130–190 °C and salinities of 3–8 wt.% NaCl eq., higher than the normal burial temperature of the basin (80–90 °C), especially meteoric fluid. Raman and gas-chromatographic analyses indicate carbonaceous matter, CH₄, CO₂, H₂ and minor O₂. Pyrite δ³⁴S values of −49.24‰ to −23.1‰ indicate isotopically light reduced sulfur ultimately related to microbial sulfate reduction and/or thermal decomposition of sulfur-bearing OM, whereas thermochemical sulfate reduction was unlikely to be dominant. Therefore, the ore-forming fluid is interpreted as a low-temperature, low-salinity organic-rich fluid, most likely derived from U-enriched source rocks at depth, and the uranium mineralization is closely associated with the exudation of such deep-derived organic fluids. Full article

Flexible thermoelectric textiles have emerged as promising materials for wearable energy harvesting and electrothermal applications because they combine mechanical flexibility with the ability to convert low-grade heat into electrical energy. In this study, reduced graphene oxide/zinc oxide/copper oxide (rGO/ZnO/CuO) hybrid nanocomposites were synthesized and deposited onto Cotton–Nylon–Spandex (80:15:05) stretch fabrics using a silicone elastomer-assisted coating process to develop flexible conductive textiles. The influence of nanocomposite loading (2–8 g/100 mL elastomer) on the structural, electrical, thermal, and thermoelectric properties of the coated fabrics was systematically investigated. SEM, EDX, XRD, and Raman analyses confirmed the successful formation and uniform distribution of the rGO/ZnO/CuO hybrid coating on the textile substrate. Increasing the nanocomposite loading progressively reduced the electrical resistance from approximately 42 to 18 MΩ, indicating the formation of an interconnected conductive network, while the Seebeck coefficient increased from 0.049 to 0.056 mV K⁻¹ (49–56 μV K⁻¹). The measured effective thermal conductivity of the coated textile decreased from approximately 12 to 2.68 W m⁻¹ K⁻¹, reflecting changes in the thermal transport behavior of the composite coating. The coated fabrics also exhibited stable electrical performance under repeated bending, stretching (up to 80% strain), and washing, together with improved thermal stability and uniform Joule-heating behavior. These results demonstrate that the rGO/ZnO/CuO hybrid coating provides an effective strategy for developing flexible, mechanically durable, and multifunctional conductive textiles with potential applications in wearable thermoelectric energy harvesting and smart heating systems. Full article

This review presents a comprehensive analysis of the physicochemical mechanisms underlying surface engineering of Cu–Zn alloys through femtosecond laser processing. It focuses on the coupled evolution of laser-induced plasma formation, selective ablation, nonequilibrium Zn redistribution, and plasma-assisted oxidation. Experimental and theoretical evidence indicates that ZnO formation cannot be explained by gas-phase reactions or surface oxidation alone, but results from the interplay of plasma processes, diffusion-controlled Zn redistribution, and heterogeneous oxidation under nonequilibrium conditions. A plasma–surface–diffusion framework is employed to interpret these coupled processes, linking selective Zn redistribution, plasma-assisted oxidation, and ZnO formation within the laser-modified surface layer. The review discusses ZnO evolution, including the influence of supersaturation, defects, and relaxation times, and highlights the effects of laser-induced structuring on reaction kinetics, energy redistribution, and mass transport. Comparison with plasma-assisted and gas-phase ZnO synthesis demonstrates common kinetic stages while emphasizing the localized and transient nature of femtosecond laser processing. This integrated interpretation provides a mechanistic basis for controlled ZnO formation. Overall, ZnO formation on Cu–Zn alloys is interpreted through a multiscale physicochemical approach integrating nonequilibrium electron excitation, plasma evolution, Zn redistribution, heterogeneous oxidation, and surface morphology, providing a framework for the rational optimization of laser-functionalized brass surfaces. Full article

Lead-free double-absorber perovskite solar cells offer broad-spectrum absorption and environmental benefits, but their multilayer heterostructure creates computational challenges for conventional design optimization. This study introduces an automated framework integrating SCAPS-1D simulation, multilayer perceptron (MLP) surrogate modeling, metaheuristic algorithms, and reinforcement learning (RL). Using FTO/ZnO/Cs₂TiBr₆/RbGeI₃/CuI/Au cells, the MLP model trained on Latin hypercube sampling data achieved high accuracy (R² > 0.95). The proximal policy optimization (PPO) RL agent converged to 27.41% power conversion efficiency (PCE) in approximately 20 steps. For direct 15-dimensional optimization, simulated annealing and particle swarm optimization reached 98% target PCE with 138 and 111 function evaluations, respectively, while Grey Wolf Optimizer (GWO) yielded the highest average PCE. Transfer learning successfully adapted the pretrained model to a novel FASnI₃/Sb₂S₃ structure, improving the prediction accuracy of PCE, J_SC, and FF. This work systematically optimizes Cs₂TiBr₆/RbGeI₃ solar cells while establishing an efficient, generalizable paradigm for intelligent photovoltaic device design, validation, and material discovery. Full article

The antibiotic and drug resistance of various bacterial and fungal strains poses a significant challenge to medicine and industry. The subject of numerous studies is how to limit the spread of microorganisms and biofilm formation on various surfaces. This research focuses on the antibacterial and antifungal properties of cross-linked methacrylate-based composites for specific applications. These composites were modified using 10 wt.% of compounds with scientifically proven antimicrobial properties. These include nanosilver, copper sulphate, benzethonium chloride, and zinc oxide. The antimicrobial potential against the following bacteria and fungi was determined: Gram-positive bacteria (Staphylococcus aureus); Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli); and the pathogenic fungi Candida albicans and Aspergillus niger. Using the modified disc-diffusion method alongside a serial dilution method demonstrated an inhibitory effect on the viability and formation of bacterial and fungal biofilms. It was demonstrated that—in liquid cultures—composites containing benzethonium chloride inhibited the growth of P. aeruginosa by over 75%, more than 50% of E. coli and more than 70% of S. aureus. Growth inhibition of C. albicans exceeded 80% for selected composites (BPA.DM + NVP + CuSO₄, BPA.DM + NVP + ZnO), while all composites inhibited the growth of A. niger by more than 45%, and in some cases (BPA.DM + HEMA + CuSO₄, BPA.DM + HEMA + Ag, BPA.DM + MMA + Ag and BPA.DM + AEH + CuSO₄) by more than 90%. Additionally, these composites significantly reduced biofilm formation on their surfaces. Modification with zinc oxide and benzethonium chloride resulted in materials that were non-toxic to normal human skin fibroblasts. To sum up the obtained results, it can be stated that these multifunctional materials with antibacterial properties could be used in medical devices, coatings, and other specialised applications where microbial contamination is a significant issue. Full article

Multicomponent ferrite oxides with mixed valence states and tunable oxygen-defect chemistry are promising active materials for low-power memristive synapses. In this work, Ag/Ni_0.3Cu_0.2Zn_0.5Co_0.005Mn_0.005Fe_1.99O/Ag memristors were fabricated by pulsed laser deposition, and the effects of post-deposition annealing at 700–900 °C on film structure, chemical states, magnetic behavior, resistive switching, and synaptic performance were investigated. The film annealed at 800 °C exhibited a dense surface morphology, improved crystallinity, and uniform elemental distribution. X-ray photoelectron spectroscopy confirmed the coexistence of Fe²⁺/Fe³⁺ states and oxygen-related defect components, indicating the presence of oxygen vacancies. Room-temperature magnetic hysteresis measurements revealed ferrite-type magnetic behavior in the annealed films, with the 800-annealed sample showing a relatively well-defined normalized hysteresis response. The optimized device exhibited representative bipolar resistive switching within ±0.5 V, distinguishable high- and low-resistance states, Ohmic conduction in the low-resistance state, and Schottky-emission-dominated transport in the high-resistance state. These results suggest that reversible oxygen-vacancy migration and interfacial barrier modulation govern the switching process. The device showed preliminary synaptic-like transient current responses. Further systematic reliability and conductance-modulation measurements are still required to fully evaluate endurance, reproducibility, and synaptic weight-update behavior. This study demonstrates that annealing-controlled multicomponent ferrite oxides offer a feasible route for energy-efficient memristive synaptic devices. Full article

This study presents a numerical investigation of heat transfer enhancement in a corrugated channel equipped with concave-up obstacles and hybrid nanofluids. The novelty of the present work lies in the combined evaluation of a new obstacle configuration with five different nanoparticles and hybrid nanofluids at two volume concentrations using both single-phase and two-phase numerical models. Numerical simulations were carried out using ANSYS Fluent 19.2 with a two-phase mixture model. Five types of nanoparticles (${\mathrm{S}\mathrm{i}\mathrm{O}}_2$, ${\mathrm{T}\mathrm{i}\mathrm{O}}_2$, ${\mathrm{A}\mathrm{l}}_2{\mathrm{O}}_3$, ZnO, and CuO) were tested at volume fractions of 1% and 2%, with obstacles optimized in size and position to enhance fluid mixing, over a Reynolds number range of 10,000–30,000. The combined application of concave-up obstacles and nanofluids increased the heat-transfer performance by approximately 244% in terms of percentage enhancement (PE) relative to the baseline corrugated channel using water without obstacles. Despite a considerable pressure drop (up to 15.5 times the baseline pressure ratio (PR)), the performance evaluation coefficient (PEC) indicates an effective trade-off, with the ${\mathrm{A}\mathrm{l}}_2{\mathrm{O}}_3$–ZnO (50:50) hybrid nanofluid (Case 2) achieving a balanced thermal–hydraulic performance with a PEC of 1.28. These findings demonstrate that the combined application of corrugated channels, obstacles, and hybrid nanofluids is a highly effective strategy for improving heat exchanger efficiency in practical applications. Full article

In this study, the cooling performances of various nanofluids were compared under the operating conditions of a real automobile radiator, based on an internal combustion engine vehicle cooling system whose experiments had been previously completed. In the analyses, the radiator inlet fluid temperature was fixed at 70 °C, air inlet velocities were set to 6, 8, and 10 m/s, and fluid flow rates were taken as 17, 19, and 21 L/min. Under these conditions, the cooling capacities were evaluated for three different working fluids whose thermophysical properties were experimentally determined: 100% pure water, water-based 0.3% ZnO nanofluid, and water-based 0.3% ZnO + CuO hybrid nanofluid. Within the scope of this study, a Computational Fluid Dynamics (CFD) model was developed based on the aforementioned experimental parameters and validated with a maximum deviation of 6%. Using the validated model, additional CFD analyses were performed for water-based 0.3% Al₂O₃ and TiO₂ nanofluids, whose thermophysical properties were also experimentally determined, and their cooling performances were assessed. Based on the experimental and numerical results obtained, the highest cooling capacity was determined to be 20.8 kW in the 0.3% TiO₂ nanofluid, representing a 69.1% increase in cooling capacity compared to pure water. These findings clearly demonstrate that the use of nanofluids significantly enhances heat transfer performance in automotive cooling systems. Full article

Significant amounts of smelting slag are generated during the production of steel, refined copper, and refined magnesium. These slags contain abundant valuable metallic elements, such as Fe, Cu, Zn, Co, and Mg, that have not been fully utilized in the past. This study proposes a method for modifying copper slag by mixing it with steel slag and magnesium slag, followed by roasting with additions of Fe₂O₃ and MgO. The samples were roasted at 1400 °C for 30 min, cooled to 1000 °C at 1.5 °C/min, and then water-quenched to room temperature. Phase transformations during modification were analyzed using FactSage 8.0, DSC–TG, and XRD. The effects of factors such as the content of Fe₂O₃ and MgO on the modification efficiency were investigated. The results indicate that, under the condition of maintaining a steel slag: copper slag: magnesium slag ratio of 37:37:26 and adjusting the basicity (CaO/SiO₂ ratio) with CaO to 2.0, the addition of Fe₂O₃ and MgO promotes the formation of spinel. However, excessively high contents of Fe₂O₃ and MgO lead to refinement of the spinel grains and reduce the iron grade of the concentrate. Within the investigated composition range, the samples with total Fe₂O₃ and MgO contents of 27.66 wt% and 7.56 wt%, respectively, showed the best magnetic separation performance among the tested compositions. Through magnetic separation, the concentrate has good economic and industrial application value in industries such as steelmaking and powder metallurgy, while the tailings can be utilized as raw materials for manufacturing ceramics, glass–ceramics, cement, and concrete. Full article

The aim of the study was to compare the production results, slaughter value, and physicochemical and biochemical parameters of the muscles of Ross 308 broiler chickens. The study included 225 individuals divided into three groups of 75 birds each. Each group was subdivided into three subgroups of 25 birds each (replicates). The control group received zinc (Zn) in the form of zinc oxide (ZnO) and copper (Cu) in the form of copper (II) sulfate pentahydrate (CuSO₄·5H₂O). Experimental group I received the microelements zinc and copper exclusively in the form of zinc hydroxychloride and dicopper chloride trihydroxide. Experimental group II received zinc and copper in both inorganic and hydroxychloride forms. The obtained results were processed using statistical analysis using the STATISTICA 13.0 [2016] program. The significance of differences between groups was inferred based on Tukey’s test. Chickens from the experimental groups were characterized by higher body weight (p ≤ 0.05) and eviscerated carcass weight (p ≤ 0.05) and better feed utilization (p ≤ 0.05). Moreover, compared with the control group, the carcasses of chickens from the experimental groups were characterized by a lower weight of breast muscles (p ≤ 0.05) and skin with subcutaneous fat, a similar weight of leg muscles, and a significantly greater weight of the remaining carcass components (p ≤ 0.01). The use of Zn and Cu in the form of hydroxychlorides in broiler chicken nutrition increased the fat content in the muscles (p ≤ 0.05), the concentrations of Zn and Cu in the liver, and significantly improved the tibial bone strength of broiler chickens. The application of Zn and Cu in the form of hydroxychlorides in the diets (experimental groups I and II) enhanced lipid and protein oxidation processes and the overall antioxidant capacity in the breast muscle. To conclude, dietary supplementation with zinc and copper hydroxychlorides in broilers promotes growth performance, bone strength, and mineral bioavailability, though it reduces breast muscle yield and triggers oxidative stress in these tissues. Full article

Microbiologically induced concrete corrosion (MICC) poses a severe challenge to the long-term durability of infrastructure, particularly in sewer networks and marine environments, which is driven by microbial metabolic activities that attack cement hydrates (Ca(OH)₂, C-S-H) mainly caused by biogenic sulfuric acid (from sulfur-oxidizing bacteria) or organic acids (from fungi), converting them into expansive gypsum and ettringite, and then cause cracking and spalling. This article reviews advances in mechanisms, key microorganisms, and protection strategies of MICC to enhance our understanding of MICC and provide a guideline for effective protection. The corrosion mechanisms differ by environment: sewers exhibit three-stage pH-driven succession, marine biofilms can either accelerate or inhibit corrosion, while fungi dominate in agricultural and historical settings. Core functional microorganisms involved in MICC include sulfur-oxidizing bacteria (SOB), sulfate-reducing bacteria (SRB), and acid-producing fungi (AF), following pH-dependent succession, while indicator microorganisms for protection efficacy include typical SOB, SRB, and AF that are involved in MICC, as well as general antimicrobial indicator strains (e.g., Escherichia coli and Staphylococcus aureus) which are used only to assess broad antimicrobial activity and do not represent MICC-specific resistance. Multi-scale deterioration proceeds from microstructural decalcification and pore coarsening to macroscopic mass loss and compressive strength reduction. Protection strategies are categorized into: (i) corrosion-resistant materials (e.g., calcium aluminate cement and alkali-activated materials), (ii) antimicrobial additives (e.g., nano-ZnO and Cu₂O), (iii) surface coatings (e.g., superhydrophobic coatings and electrodeposited Cu/Cu₂O layers), and (iv) ecological regulation. However, significant gaps remain between laboratory efficacy and field performance, highlighting the need for long-term validation, multi-scale characterization, intelligent responsive materials, eco-compatible protection systems, and standardized microbial exposure systems. Full article

In this study, a series of Cu_aZn_bO_x catalysts with tunable Cu/Zn molar ratios were fabricated via a MOF-on-MOF precursor strategy for CO₂ hydrogenation to methanol. The optimal catalyst, Cu₆Zn₄O_x, achieved a CO₂ conversion of 14.4%, a methanol selectivity of 81.1%, and a space-time yield of 902.1 g_MeOH·kg_cat⁻¹·h⁻¹ at 280 °C and 3 MPa with a GHSV of 24,000 mL·g_cat⁻¹·h⁻¹. Characterization results revealed that this strategy successfully constructed small-sized Cu and ZnO particles as well as abundant Cu–ZnO interfaces, reaching the optimal structural and compositional state when the Cu/Zn molar ratio is tuned to 6:4. The effective Cu–ZnO interface on Cu₆Zn₄O_x promotes the CO₂ adsorption and H₂ dissociation, triggering the formation of carbonate species and resulting in the generation of methanol via a carbonate–formate pathway. This work provides a new insight for the rational design of high-performance CO₂ hydrogenation catalysts through precursor interface engineering. Full article

Metal oxide nanoparticles serve as crucial drivers in modern biomedical, catalytic, environmental, and energy technologies due to their high surface-to-volume ratios and quantum confinement properties. Traditional chemical and physical synthesis methods remain limited by significant energy footprints, high costs, and the use of hazardous reagents. To address these challenges, bioinspired (“green”) synthesis has emerged as a sustainable paradigm that employs biological systems as nature nanofactories. This critical review provides a provides a comprehensive and systematic analysis of the green synthesis of major metal oxide systems (ZnO, TiO₂, Fe₃O₄/Fe₂O₃, CuO, Co₃O₄, CeO_2, and MnO₂) using diverse biological templates, including plant extracts, bacteria, fungi, algae, and biopolymers. Moving beyond simple descriptive summaries, we critically evaluate the foundational electron-transfer and nucleation mechanism, systematically correlate processing parameters with physical outcomes, and offer a rigorous comparative analysis across different biological kingdoms. Finally, we directly address the underlying challenges facing the field: reproducibility bottlenecks, scalability limits, environmental safety variations, and regulatory hurdles necessary for industrial translation. Full article

Radiation therapy is widely used for cancer treatment. To improve therapeutic efficacy, traditional radiosensitizers are often used in combination. However, their toxic side effects necessitate urgent development of safer alternative biogenic radiosensitizers. Herein, a green approach was used to synthesise ZnO NPs, CuO NPs, and ZnO-CuO NCs using S. africana Luteus, and their ability to enhance the radiosensitizing effect of proton irradiation on Michigan Cancer Foundation-7 (MCF7) breast cancer cell line was evaluated. The biogenic nanoparticles are characterised in detail through several analytical techniques, including Ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM). Interestingly, the NPs showed concentration-dependent effects on MCF7 viability, with CuO NPs exhibiting the strongest effect (IC₅₀ = 42.90 µg/mL), followed by ZnO-CuO NCs (71.12 µg/mL) and ZnO NPs (103.43 µg/mL). Proton irradiation produced a dose-dependent decrease in clonogenic survival of MCF7 cells, and ZnO-CuO NCs displayed the highest enhancement of proton-induced cell death, with a Dose Enhancement Factor (DEF) of 1.69, compared with CuO NPs (1.46) and ZnO NPs (1.09). Holotomographic microscopy (HTM) data further confirmed that ZnO-CuO NCs impaired cellular macromolecules more than the individual NPs. Findings from this study suggest that the biogenic NPs are promising radiosensitizers for cancer radiotherapy. Full article