Search Results (456)

The increasing presence of microplastics in the aquatic and terrestrial food chains calls for the need to come up with innovative and effective remediation approaches. Such innovations as zinc oxide (ZnO) structures and metal–organic frameworks (MOFs) are examined as the second generation of photocatalysts for degrading microplastics under sunlight. We will focus on the latest advances and discuss the structure of photocatalytic processes, their functioning under various light conditions, and their environmental impacts, especially environmental safety and ecotoxicity. ZnO structures are even better photocatalysts because they form reactive oxygen species (ROS) as good as other metal oxides. However, their possible cytotoxicity and the ability to generate oxidative stress require serious evaluation. MOFs, on the contrary, offer physicochemical properties, environmental safety, ecotoxicity, and environmentally friendly synthesis pathways, making them a worthy substitute. The review underscores the urgency of incorporating environmental safety and ecotoxicity into the design of photocatalysts, thereby unlocking their full potential while avoiding environmental or human health risks. Moving forward in the field of sustainable nanotechnology to remove microplastics will provide the way to come up with green innovations and hence guarantee the effectiveness of combating plastic pollution in long-term stability. Full article

In this study, Zn-doped Co₃O₄ nanorods and nanosheets with controlled Zn/Co molar ratios were synthesized via a hydrothermal strategy to clarify the respective roles of morphology and elemental doping in ethylbenzene sensing. The gas-sensing performance is strongly influenced by morphology, and the radially oriented nanorod structure significantly enhances sensing response compared with nanosheet structures. Zn doping effectively enhances the gas-sensing performance of Co₃O₄. As a result, the optimized Zn-doped nanorod sensor exhibits high sensitivity to ethylbenzene, a low detection limit, rapid response and recovery, and excellent operational stability. Density functional theory calculations reveal that the predominantly exposed facets of the nanorod structure possess stronger adsorption affinity and pronounced charge transfer toward ethylbenzene, providing theoretical support for the morphology-dominated sensing behavior. At the same time, Zn incorporation further adjusts the band structure and surface reactivity. Overall, this work elucidates a morphology-dominated and doping-assisted enhancement mechanism, offering clear design principles for high-performance Co₃O₄-based ethylbenzene sensors. Full article

Zinc oxide (ZnO) nanomaterials have attracted widespread attention from researchers due to their morphology-dependent properties, eco-friendly characteristics, and potential as a sustainable photocatalyst with a broad range of applications. Therefore, in this study, three different ZnO nanostructures—nanosheets (NSs), nanoflowers (NFs), and nanorods (NBs)—were synthesized via a controlled precipitation method. Among these, NFs exhibited the highest photocatalytic efficiency. The obtained samples exhibited broad optical absorption edges extending into the visible region (corresponding to apparent energies of 1.81–2.09 eV), which is attributed to the sub-bandgap states induced by oxygen vacancies rather than intrinsic bandgap narrowing—far lower than the bandgap of bulk ZnO (3.37 eV). Their photocatalytic performance was evaluated by the degradation of Methyl Blue (MB), Methyl Orange (MO), and Rhodamine B (RhB) under UV or sunlight. Notably, the NFs achieved rapid degradation of MB and RhB within 90 min under UV irradiation without the addition of any H₂O₂, demonstrating their effectiveness and cost-effectiveness for practical applications. Although H₂O₂ inhibited the degradation of MB and RhB, it promoted the decomposition of MO. Furthermore, the ZnO NFs exhibited excellent recyclability in five consecutive degradation cycles. The self-synthesized ZnO nanomaterials in this study, with their broad-spectrum absorption, high stability, and eco-friendly properties, demonstrate their potential as an efficient and low-cost photocatalyst for large-scale wastewater treatment. Full article

This study investigates the properties of ZnO nanorod-based sensors and ZnO nanorods modified with tin dioxide (ZnO/SnO₂) and gold (ZnO/Au) nanoclusters and their response to low concentrations of carbon monoxide (CO). It was demonstrated that the ZnO/SnO₂(3) nanorod-based sensor exhibited the highest sensitivity (S = 1.64) to 10 ppm CO, while the ZnO/Au(3) sensor displayed the shortest response (69–207 s) and recovery (203–233 s) times. This behavior can be explained by ZnO/Au and ZnO/SnO₂ nanostructures having low activation energies (0.23–0.25 eV) and high potential barrier values (0.37–0.43 eV). Sensors based on ZnO/Au and ZnO/SnO₂ nanorods demonstrate sensitivity to 10 ppm CO at 250 °C and at 200 °C. In contrast, ZnO nanorod-based sensors are sensitive to 2 ppm CO at 250 °C. Full article

Due to the non-polar and chemically inert nature of carbon fiber surfaces, the interfacial bonding strength between carbon fibers and norbornene-polyimide (PI-NA) resin matrix is relatively weak. To address this issue, this study constructed a composite coating on the carbon fiber surface and proposed a novel method to build robust interfaces based on multiple interfacial interactions, thereby effectively enhancing the interfacial properties between carbon fibers and PI-NA resin. Inspired by mussel adhesive proteins, this study established a multi-level synergistic interfacial reinforcement system by sequentially constructing a C-PEI@OPDA coating, in situ growing zinc oxide nanorods (ZW) arrays, and grafting 3-mercaptopropyltrimethoxysilane (MPS) onto carbon fiber surfaces. The C-PEI@OPDA coating, rich in amino (–NH₂) and hydroxyl groups (–OH), enhanced adhesion to carbon fibers and adsorbed Zn²⁺ via coordination interactions to provide nucleation sites for ZW growth. Meanwhile, the active hydrogen in the coating promoted the crosslinking of PI-NA resin, thereby increasing the resin crosslinking density in the interfacial region. The vertically aligned ZW significantly increased surface roughness, enhanced mechanical interlocking effects, and provided secondary reaction sites for MPS grafting. The thiol groups (–SH) in MPS formed covalent bonds with PI-NA resin through thiol-ene click reactions, further strengthening interfacial bonding. The results showed that the ILSS, IFSS, and flexural strength of C-PEI@OPDA/ZW/MPS modified carbon fiber composites reached 75.15 MPa, 102.93 MPa, and 1735.56 MPa, representing improvements of 39.09%, 48.79%, and 31.16%, respectively. This study effectively enhanced the carbon fiber-reinforced polymer composites interfacial bonding strength through the synergistic effects of hydrogen bonding, mechanical interlocking, chemical bonding, and increased resin crosslinking density. Full article

In this study, an enzyme-free electrochemical sensor based on zinc oxide (ZnO) nanorods synthesized by the thermal decomposition of zinc acetate is presented. The suggested approach ensures simplicity, environmental friendliness, and scalability of the process without the use of an autoclave or high pressure. The morphology and structure of the samples are studied using SEM, TEM, XRD, Raman, FTIR, XPS, PL, and UV-Vis spectroscopy. It is found that heat treatment at 450 °C increases the degree of crystallinity, increases the size of crystallites, and reduces the concentration of surface defects, which leads to improved optical and electrochemical characteristics of the material. Beyond conventional sensitivity metrics, our study demonstrates that the selective detection of ascorbic acid (AA) and uric acid (UA) can be achieved by controlling the applied potential on a single ZnO electrode, an approach that leverages differences in redox energetics and surface interaction dynamics rather than complex surface functionalization. It is shown in this work that the synthesized ZnO samples subjected to heat treatment in air at 450 °C exhibit high sensitivity to ascorbic acid (9951.87 μA·mM⁻¹·cm⁻²; LoD = 1.11 μM) at a potential of 0.2 V and to uric acid (5762.48 μA·mM⁻¹·cm⁻²; LoD = 1.71 μM) in a phosphate buffer solution (pH 7) at a potential of 0.4 V with a linear range of 3 mM, offering a way to create simplified multicomponent electrochemical biosensors based on potential-controlled selectivity. Full article

Monitoring uric acid (UA) concentration is crucial for human health, enabling early detection and prevention of metabolic disorders as well as assessing renal function and overall metabolic balance. Herein, we developed a field-effect transistor (FET)-based UA biosensor using hydrothermally synthesized vertical zinc oxide (ZnO) nanorods (NRs) and uricase. The fabricated FET biosensor was tested in phosphate-buffered saline (PBS) at increasing UA concentrations to evaluate its biosensing performance. The FET biosensor yields a sensitivity of 12.45 μA·mM⁻¹·cm⁻², covering a dynamic range of 0.05–2.75 mM. The calculated detection limit was ~0.0043 mM. The improved sensing performance results in a substantial enhancement of both detection sensitivity and limit of detection compared to the traditional lateral electrode setup. Additionally, selectivity, storage stability, fabrication reproducibility, and applicability for serum UA detection were evaluated. Overall, the vertical electrode configuration of the UA biosensor has the potential to be further extended for the sensitive detection of additional biomarkers. Full article

To achieve high-performance photocatalysts, efficient separation of photogenerated charge carriers is critical to prolonging their lifetime and thereby enhancing the activity of the hydrogen evolution reaction. In this work, we rationally designed and synthesized a nanoflower-like SrSnO₃/ZnIn₂S₄ heterostructure by in situ embedding SrSnO₃ nanorods within the layered framework of ZnIn₂S₄. Experimental results demonstrate that the 0.8%-SrSnO₃/ZnIn₂S₄ composite exhibits a hydrogen evolution rate 13.79 times higher than that of pure ZnIn₂S₄ under simulated solar irradiation. This dramatic enhancement stems from the formation of a Type-II heterojunction at the interface, where the staggered band alignment generates an internal electric field that drives spatial separation of electrons and holes, effectively suppressing recombination and promoting charge utilization. This study validates that the strategic incorporation of a small amount of SrSnO₃ into ZnIn₂S₄ represents a highly effective approach to significantly boost photocatalytic hydrogen production performance. Full article

Efficient oil-water separation remains a major challenge in oily wastewater treatment, highlighting the need for advanced materials that combine superwettability, structural durability, and long-term recyclability. Here, we develop a hierarchical ZOMO-PAA@CuC₂O₄ NR@CM membrane via sequential chemical oxidation, oxalic acid etching, and spray-coating of ε-Keggin-type Na-ZnM ZOMO nanoparticles within a polyacrylic acid (PAA) matrix. The resulting architecture couples CuC₂O₄ nanorods with hydrophilic ZOMO-PAA coatings to achieve superhydrophilicity and underwater superoleophobicity. Structural characterization confirmed uniform nanoparticle dispersion, high crystallinity, and robust framework integrity. The membrane exhibits ultrafast water spreading (0°), underwater oil contact angles above 150°, and sliding angles as low as 4°, enabling broad-spectrum oil repellence, antifouling, and self-cleaning. The as-prepared membrane efficiently separates both surfactant-free and surfactant-stabilized emulsions, including aliphatic and aromatic oils stabilized by cationic, anionic, and non-ionic surfactants, with high water fluxes (1695–2675 L·m⁻²·h⁻¹ and ~900 L·m⁻²·h⁻¹, respectively) and separation efficiencies above 99.1%. The membrane further demonstrates chemical stability under acidic, alkaline, and saline conditions, alongside consistent oil–water separation behavior across multiple cycles. These findings establish ZOMO-PAA@CuC₂O₄ NR@CM as a robust and scalable platform for advanced oily wastewater treatment. Full article

In this study, ZnO thin films were prepared on the flexible stainless steel (FSS) substrates by the sol–gel method. ZnO nanorods were then hydrothermally grown in the presence of polyvinyl pyrrolidone (PVP) to obtain polymer/nanooxide composites. The microstructure and resistive switching properties of the composites were investigated. X-ray diffraction results confirmed that the PVP-doped ZnO nanorods retained the hexagonal wurtzite structure and had a preferred (002) orientation despite a slight decrease in crystallinity. Surface morphology analysis showed that the addition of PVP resulted in an increase in the nanorod density and a more regular hexagonal structure. Electrical measurements showed a significant improvement in the resistive switching behavior, with a high-resistance state to low-resistance state (HRS/LRS) ratio of 4.67 × 10³. In addition, radiation-tolerant cyclic tests demonstrated that the polymer–oxide hybrid structure effectively buffered irradiation-induced defects, stabilized conductive filament pathways, and preserved switching reliability. These results highlight the potential of PVP-doped ZnO nanorod composites as reliable, flexible, and radiation-tolerant RRAM devices for future aerospace and high-radiation electronics applications. Full article

Background: Biomedical device-associated infections pose major challenges in surgical care, particularly in hernia repair where polypropylene (PP) meshes and sutures are prone to bacterial colonization and biofilm formation. The limitations of antibiotic resistance and toxicity warrants the need of developing innovative antibacterial strategies. Methods: We developed a composite coating of hydroxypropyl methylcellulose (HPMC) and zinc oxide nanorods (ZnO NP) synthesized via thermal decomposition. This coating was applied to PP meshes and sutures to enhance anti-adhesive properties. The study evaluated surface hydrophilicity through water contact angles, estimation of Zn²⁺ ions using inductively coupled plasma–mass spectrometry (ICP-MS), and long-term efficacy over six months. Safety was assessed via systemic toxicity studies in murine models. Results: The ZnO NPs exhibited potent antibacterial efficacy, achieving up to 99.999% killing against Klebsiella pneumoniae. When applied as an HPMC-ZnO coating, PP meshes and sutures demonstrated enhanced hydrophilicity, reducing water contact angles by ~41° and facilitating prevention of bacterial adhesion. The coated meshes inhibited bacterial attachment by 83% (Escherichia coli), 60% (Pseudomonas aeruginosa), 99.6% (K. pneumoniae), and 99% (Staphylococcus aureus). Similarly, coated sutures reduced adhesion by 67–96% across these strains. Long-term storage studies showed retained antibiofilm efficacy for up to six months. In vivo assessments indicated negligible systemic toxicity of ZnO NPs in murine models. Conclusions: Collectively, these findings highlight HPMC-ZnO NPs coatings as a safe, durable, and effective strategy to functionalize PP-based meshes and sutures, reducing the risk of surgical site infections and demonstrating the potential for broader biomedical applications. Full article

Developing precise tumor-targeting delivery systems while minimizing off-target toxicity continues to pose significant challenges in medicine application. The integration of two different functional materials has emerged as a promising strategy in current biomedical research. Herein, a hybrid nanocomposite consisting of Fe₃O₄ and ZnO was synthesized via a simple approach and employed as a nanoscale drug delivery system to explore the loading capacity and stimuli-responsive release characteristics of the anticancer agent doxorubicin (DOX). Results show that the synthesized nanoparticles (NPs) exhibit a multi-scale nanostructure consisting of the spindle-like ZnO nanorods with a mean length of 280 nm, on which the Fe₃O₄ NPs with a diameter of around 16 nm are uniformly dispersed. The ZnO@Fe₃O₄ NPs possess superparamagnetic behavior and a fast response to the external magnet and demonstrate exceptional near-infrared (NIR) photothermal conversion efficiency. In drug release studies, the ZnO@Fe₃O₄ NPs achieve the controlled DOX release in the simulated acidic tumor microenvironment as well as NIR laser irradiation. Further, the ZnO@Fe₃O₄-DOX composites significantly suppress the viability of human cervical cancer cells (HeLa) upon laser activation. These findings suggest that ZnO@Fe₃O₄ NPs are promising candidates for combined photothermal therapy, magnetic-targeted drug delivery, and stimuli-responsive controlled release applications. Full article

In this work, hollow-structured nanofibers with densely and uniformly distributed ZnO nanorods were successfully prepared by a combination of coaxial electrospinning, heat treatment, and hydrothermal synthesis, exhibiting excellent photocatalytic degradation performance. The morphological and structural characteristics of hollow ZnO nanofibers obtained at different heat treatment temperatures were systematically investigated, and their photocatalytic degradation performances were compared through degrading methylene blue (MB) under ultraviolet (UV) irradiation. It was found that the hollow ZnO nanofibers obtained by heat treatment at 280 °C exhibited the best photocatalytic degradation performance due to their optimal morphology and structure. Their photocatalytic degradation efficiencies for MB under 3 h of UV light and natural sunlight were 94.70% and 92.95%, respectively. Furthermore, cyclic stability tests were conducted on the optimal sample, revealing that its degradation efficiency remained at 89.96% after three cycles, demonstrating its excellent reusability. Full article

The growing demand for sustainable food packaging has driven the development of active packaging systems using biopolymers like poly(lactic acid) (PLA) and natural antimicrobials. This study focuses on creating novel nanohybrids by loading carvacrol (CV) and trans-cinnamaldehyde (tCN) onto ZnO nanorods for incorporation into PLA/triethyl citrate (TEC) films. The CV@ZnO and tCN@ZnO nanohybrids were synthesized and characterized using XRD, FTIR, desorption kinetics, and by assessing their antioxidant and antibacterial properties. These nanohybrids were then integrated into PLA/TEC films via extrusion. The resulting active films were evaluated for their physicochemical, mechanical, barrier, antioxidant, and antibacterial properties. The tCN@ZnO nanohybrid exhibited a stronger interaction with the ZnO surface and a slower release rate compared to CV@ZnO. While this strong interaction limited its direct antioxidant activity, it proved highly beneficial for the final film’s performance. Films containing 10% tCN@ZnO demonstrated the strongest antibacterial efficacy in vitro against Listeria monocytogenes and Escherichia coli and functioned as potent mechanical reinforcement fillers. Crucially, in a practical application, the PLA/TEC/10tCN@ZnO film significantly extended the shelf-life of fresh minced pork during 6 days of refrigerated storage. It effectively suppressed microbial growth (TVC), delayed lipid oxidation (lower TBARS values), and preserved the meat’s colour and nutritional quality (higher heme iron content) compared to control packaging. The developed tCN@ZnO nanohybrid is confirmed to be a highly effective active agent for creating PLA/TEC-based packaging that can enhance the preservation of perishable foods. Full article

Organic pollutants pose a significant threat to both the ecological environment and human health. In this study, BiVO₄@ZnO heterojunction composites were synthesized via a two-step hydrothermal method. The incorporation of polyhedral BiVO₄ onto the flower-like structure of ZnO effectively enhanced the photocatalytic performance of the composite. Compared with ZnO flower-like nanorods, the BiVO₄@ZnO heterojunction composite photocatalysts achieved degradation efficiencies of 93.18% (k = 0.09063) and 89.64% (k = 0.007661) for methylene blue (MB) within 30 min under ultraviolet and visible light irradiation, respectively. The photocatalytic activity of the BiVO₄@ZnO composites was also evaluated against various organic dyes, including rhodamine B (RhB), Congo red (CR), methyl orange (MO), and methylene blue (MB). Under ultraviolet light, the catalysts showed particularly high activity toward MB and CR. The enhanced photocatalytic performance can be attributed to two main factors: firstly, the heterojunction facilitates the separation of photogenerated electron-hole pairs, thereby improving photocatalytic efficiency; secondly, the composite exhibits a broadened and enhanced light absorption range. Furthermore, the BiVO₄@ZnO heterojunction composites demonstrate excellent cyclic catalytic stability and structural integrity. This study offers a clean and efficient strategy for the photocatalytic degradation of aqueous organic pollutants. Full article