Search Results (1,519)

High-sensitivity rapid detection of ammonia (NH₃) in environmental monitoring, industrial safety, early diagnosis, and other fields is of great significance. Covalent organic frameworks (COFs) have shown great potential in the field of gas sensing due to their designable porous structure and active sites. However, the traditional solvothermal synthesis method of COFs has problems such as cumbersome steps, high energy consumption and serious environmental pollution. Therefore, it is of great significance to invent a new method for COF synthesis that is green and efficient and makes it easy to conduct flexible ammonia gas sensing. This study first reported a solvent-free synthesis of imine connection 1,3,5-Triformylbenzene (TFB) and p-Phenylenediamine (PDA)—a new strategy for COF. This method innovatively employs zinc trifluoromethyl sulfonate (Zn(OTf)₂) as a bifunctional catalyst. This catalyst not only efficiently catalyzes para-phenylenediamine, but its zinc ions also play a unique structural guiding role, guiding the reactants to be arranged in a directional manner, thereby constructing a highly ordered porous crystal structure. A series of characterizations confirmed that the obtained TFB-PDA-COF had good crystallinity and a high proportion of imine bonds (C=N). The powder material was coated onto a flexible polyimide (PI) substrate, successfully constructing a resistive ammonia gas sensor that operates at room temperature. The test results show that this sensor has a high response value, rapid response/recovery capability, and good selectivity for ammonia gas. More importantly, based on a flexible PI substrate, the device can maintain stable sensing performance even under repeated bending conditions, demonstrating its great potential in practical flexible electronic applications. This work not only provides a brand-new “zinc ion-guided” paradigm for the green and controllable synthesis of COF but also lays a material foundation for their application in the next-generation flexible sensing field. Full article

Metal ion-based chemo-immunotherapy is often limited by rigid intracellular metal homeostasis, insufficient reactive oxygen species (ROS) accumulation, and an immunosuppressive tumor microenvironment (TME). To overcome these limitations, we engineered an ATP-responsive, core–shell bimetallic nanoreactor (Cu/ZIF@PDA, termed CZP) featuring a precisely controlled ~25 nm biomimetic polydopamine (PDA) coating. Triggered by elevated tumoral ATP levels, CZP undergoes coordination-induced disassembly and promotes oxidative stress amplification. Specifically, the PDA shell acts as a superoxide dismutase (SOD) mimetic to continuously supply H₂O₂, fueling Cu²⁺-mediated Fenton-like reactions to unleash highly toxic hydroxyl radicals (•OH) while aggressively depleting the intracellular glutathione (GSH) pool. This irreversible oxidative damage, coupled with Zn²⁺-induced mitochondrial dysfunction, triggers profound mitochondrial DNA (mtDNA) leakage. Crucially, this cytosolic DNA robustly activates the cGAS-STING signaling axis, driving a massive surge in immunogenic cell death (ICD) and significantly promoting dendritic cell (DC) maturation. Furthermore, CZP markedly inhibited primary tumor growth in vivo and showed protection in a tumor re-challenge model, accompanied by enhanced dendritic cell maturation. These findings support the potential of this ATP-responsive bimetallic nanoplatform to promote antitumor immune activation. Full article

The widespread presence of stable and hazardous organic contaminants, such as synthetic dyes, in industrial effluents necessitates the development of resilient treatment strategies capable of achieving efficient degradation and decolorization of dye pollutants. Conventional treatment processes often fail to remove such recalcitrant compounds, prompting growing interest in integrated advanced systems. Photocatalytic membranes represent a promising solution due to the synergistic combination of physical separation and catalytic degradation. In this study, zinc oxide (ZnO) thin films were deposited by spin coating onto smectite–zeolite ceramic membranes (MS10/Z90), applying one (M1), two (M2), and three (M3) successive coating layers to control catalyst thickness. SEM analysis confirmed that increasing the number of layers resulted in a thicker and more homogeneous ZnO coating, while XRD revealed enhanced crystallinity and larger crystallite size. Water permeability decreased progressively from 623 L·h⁻¹·m⁻²·bar⁻¹ for the uncoated membrane to 506, 439, and 350 L·h⁻¹·m⁻²·bar⁻¹ for M1, M2, and M3, respectively. Photocatalytic performance was evaluated using Rhodamine B (RhB) (10 mg·L⁻¹) under UV irradiation (365 nm, 18 W) for 180 min, achieving degradation efficiencies of 83.0%, 94.6%, and 99.1% for M1, M2, and M3, respectively. The degradation kinetics followed a pseudo-first-order model, with rate constants increasing with catalyst layer thickness. Free radical scavenging assays confirmed that hydroxyl radicals (•OH) were the primary reactive species responsible for RhB degradation. These findings highlight the critical influence of ZnO layer thickness and mass transfer on photocatalytic performance, demonstrating the potential of ZnO-coated ceramic membranes for efficient pollutant degradation and in situ photocatalytic regeneration. Permeability measurements after photocatalytic treatment confirmed effective flux recovery, supporting the operational durability of the developed membranes. Full article

Objective: This work aims to reduce the surface tension of an aluminum–silicon alloy melt by adding different amounts of the Zn element, thus improving the coatability and coating quality of hot-dip aluminum plating on steel plates. Method: Wetting experiments were conducted at 1023 K using a modified sessile drop method. Conclusions: The addition of the Zn element can reduce the surface tension of the Al-Si alloy, thus decreasing the wettability of the Al-Si alloy. Zn vapor can break down the surface oxide film to expose the fresh melt. The wettability of the Al-10Si alloy on interstitial-free (IF) steel and surface tension were investigated using the modified sessile drop method at 1023 K. Axisymmetric Drop Shape Analysis software was utilized to calculate the contact angles of the Al-10Si-xZn/Al₂O₃ and Al-10Si-xZn/IF steel systems (x ranges from 0 wt.% to 5 wt.%). Moreover, the microtopography and microstructure of surfaces and cross-sections were analyzed by means of an energy-dispersive spectrometer and scanning electron microscope. The results indicated that the surface tension of the alloy melt gradually decreases with an increase in Zn content, ranging from 874 to 760 mN/m. The contact angle of the Al-10Si-xZn alloy melt on IF steel also progressively decreases with increasing Zn content, which is attributed to the lower surface tension of Zn. This study also discovered that the Zn element can disrupt the oxide film of the Al-10Si alloy, exposing the fresh melt and thereby reducing the surface tension of the alloy liquid, thus enhancing wettability. The addition of Zn might be capable of improving the hot-dip aluminizing coatability of steel plates and the quality of the coating. Full article

Fungal growth and insufficient thermal comfort degrade building durability and indoor quality, especially in humid and high-radiation regions. Zinc oxide (ZnO) stands out for its strong antifungal activity and radiative cooling potential. In this study, a commercial coating was modified with ZnO nanoparticles synthesized via a green chemistry route using Cymbopogon citratus (lemongrass) leaf extract as a reducing agent. Structural and morphological characterization by XRD, SEM, and EDS confirmed the formation of hexagonal wurtzite-phase nanoparticles with hemispherical and ellipsoidal morphologies, presenting average sizes of 50.27 ± 19.84 nm and 128.25 ± 33.43 nm, respectively, and an average crystallite size of 20.32 nm. Antifungal activity, evaluated using the poisoned food technique against Aspergillus niger and Penicillium spp., showed significant growth inhibition, reaching up to 94.63% for A. niger and 72.64% for Penicillium at a concentration of 3 mg/mL after 120 h of incubation. Thermal comfort performance was assessed to direct sunlight, in which coatings modified with 5% w/w ZnO nanoparticles achieved an average internal temperature reduction of 0.6 °C and a maximum reduction of 2.4 °C compared to uncoated surfaces. These results demonstrate that ZnO nanoparticles synthesized through environmentally friendly methods can effectively enhance both antifungal resistance and passive cooling performance. Full article

We report highly sensitive NO₂ gas sensors based on ZnO thin films prepared via a sol–gel method and deposited onto nanostructured black silicon (b-Si). The b-Si layers, fabricated using maskless reactive ion etching, consist of densely packed silicon nanoneedles with an average height of ~810 nm, a base diameter of ~160 nm, and a characteristic periodicity of ~190 nm. Owing to this highly developed surface morphology, the effective surface area of the b-Si layer is estimated to be approximately one order of magnitude higher than that of planar silicon, thereby enhancing gas adsorption and charge-transfer processes in the ZnO film. ZnO/b-Si/Si sensors exhibit a response of 448% at 25 ppm NO₂ at an optimal operating temperature of 200 °C, which is approximately 1.5 times higher than that of planar ZnO/Si sensors at the same concentration and temperature. Notably, a comparable response (~300%) is achieved at a reduced temperature of 140 °C, indicating the potential for low-power operation. The sensing mechanism is governed primarily by the ZnO layer, while b-Si serves as a morphological scaffold, increasing the effective surface area. These results demonstrate that ZnO-coated b-Si nanostructures represent a promising platform for high-performance NO₂ sensing and offer strong potential for integration with silicon-based microelectronic technologies. Full article

Stainless steel (SS) remains widely used in orthopedic implants but is susceptible to corrosion and implant-associated infections in physiological environments. This study aimed to develop a multifunctional multilayer coating combining corrosion resistance, bioactivity, and antimicrobial performance. A ZnO base layer was deposited on 316L SS via pulsed laser deposition, followed by matrix-assisted pulsed laser evaporation of a lovastatin-functionalized bioactive glass (BG57 + LOV) top layer. Two LOV concentrations were initially evaluated, and BG57+0.1LOV was selected based on structural homogeneity, cytocompatibility, and antimicrobial balance. Physicochemical characterization confirmed preservation of chemical integrity and formation of continuous, moderately rough coatings. Electrochemical impedance spectroscopy in simulated body fluid demonstrated progressive improvement in corrosion resistance from bare SS to ZnO-coated and finally to the BG57+0.1LOV/ZnO multilayer, which exhibited the most electropositive corrosion potential and effective suppression of charge-transfer reactions. Biological assays revealed high viability of osteoblasts, fibroblasts, keratinocytes, and macrophages without significant oxidative or nitrosative stress. Antimicrobial testing showed strain-dependent activity, with enhanced efficacy against MRSA and significant reduction in P. aeruginosa, associated with increased ROS/RNS generation. Overall, the BG57+0.1LOV/ZnO system represents a promising multifunctional coating strategy for corrosion-resistant and infection-resistant SS implants. Full article

Zinc-based coatings are insufficient as surface coatings; they corrode rapidly and can cause long-term damage to subsea pipelines and other instruments. Therefore, this research was undertaken by manufacturing a sacrificial nano-reinforced Zn coating combined with additives via electrodeposition onto a mild steel S235 substrate, which provides excellent corrosion resistance under severe marine conditions. The electrodeposited coatings were characterized using SEM/EDS and XRD, revealing the effective incorporation of cerium oxide nanoparticles and high-quality graphene (Gr) in the zinc matrix. Vickers microhardness measurements, mechanical resilience, and surface roughness of the Zn-CeO₂-Gr coating showed an inverse correlation between improved microhardness (+65.85%) and mechanical resilience (+31.49%), while surface roughness decreased (−81.48%) compared to pure zinc electrodeposited coatings. These characteristics indicate grain refinement and greater reliability under mechanical stress. Electrochemical impedance spectroscopy (EIS) and DC polarization measurements indicate a significant improvement in corrosion resistance compared to pure zinc, due to the synergistic effect between graphene and cerium oxide nanoparticles, which reduces the cathodic activity of the surface. These findings offer promising applications for cutting-edge materials in saline environments. Full article

Stricter drinking water regulations intensify the need to replace leaded brasses in fittings. This work reports preliminary results on internally coated fittings using the wrought zinc alloy ZnAl15Cu1Mg (ZEP1510). A straight-tube Model Geometry 1 was lined internally with HDPE by gas-assisted injection molding, achieving a continuous barrier of 1.55–1.70 mm without altering the external envelope. A press-type T-fitting (32–32–32) was defined as Model Geometry 2 to benchmark forgeability; process layout (FEM) and warm-forging trials are summarized. Recycling relevance was addressed via a partial-melt (drip-off) route, which removed a substantial polymer fraction but left measurable residues. A production-cycle PCF from material production to finished tee indicates 3.156 kg CO₂e for ZEP1510 vs. 5.385 kg CO₂e (CuZn40Pb2) and 6.301 kg CO₂e (CuZn21Si3), i.e., 41.85% and 50.06% savings. These findings establish manufacturability, indicate recycling feasibility, and quantify a CO₂ advantage, outlining the next steps toward lining complex geometries and drinking water compliance. Full article

The critical role of lithium in powering the new energy economy necessitates prioritizing efficient extraction methods. This study investigates a novel zeolitic imidazolate frame work (ZIF-8)-coated manganese-based lithium-ion sieve (LIS) for enhanced lithium recovery. The precursor of LIS, Li_1.6Mn_1.6O_4, was synthesized via the hydrothermal method, followed by acid pickling to obtain the spinel lithium-ion sieve H_1.6Mn_1.6O₄. The material was then immersed in a 2-methylimidazole/Zn(NO₃)₂ solution, undergoing ultrasonic-assisted hydrothermal growth to form H_1.6Mn_1.6O₄@ZIF-8 composites. Under optimized conditions (30 °C, pH = 11, 24 h), the composite demonstrated superior lithium extraction performance compared to single-phase adsorbents, reaching 26.62 mg/g in the solution with 250 mg/L Li⁺. The adsorption capacity of the composite increased with Li⁺ concentration and reaction time. The adsorption kinetics followed a pseudo-second-order kinetic model and were dominated by chemisorption. The H_1.6Mn_1.6O₄@ZIF-8 composite exhibited an enhanced Li⁺ partition coefficient K_d of 118.3 in a mixed solution containing ions such as Li⁺, Mg²⁺, K⁺, and Ca²⁺, each with a concentration of 250 mg/L (pH = 12); good structural stability with manganese dissolution of 1.6%; and a capacity retention of approximately 79.5% after five cycles (C_Li⁺ = 250 mg/L). Full article

For the first time, hybrid nanocomposites based on poly(2,5-dichloro-3,6-bis(phenylamino)-p-benzoquinone) (PCPAB) and multi-walled carbon nanotubes (MWCNTs) were obtained and the influence of the preparation method on their structure and functional properties was demonstrated. The nanocomposites were obtained both by ultrasonic mixing of PCPAB and MWCNTs, and via in situ oxidative polymerization of CPAB in the presence of MWCNTs or MWCNTs with the addition of ZnO. The formation of hybrid nanocomposites occurs due to non-covalent interaction (π-stacking) between the graphene structures of the MWCNT surface and the phenyl rings of PCPAB. It was found that during the in situ oxidative polymerization of CPAB in the presence of MWCNTs, the growth of polymer chains occurred in close proximity to the filler surface, which led to the formation of a polymer coating. ZnO particles, localized on MWCNTs, on the one hand, prevent their aggregation, and on the other hand, create additional polymerization reaction centers due to the coordination of the Zn-O bond at the H and O atoms of the monomer. An increase in the concentration of reaction centers as a result led to a 2–2.5-fold reduction in the induction polymerization period. According to SEM data, in this case, a more ordered and denser polymer layer is formed due to intermolecular complexation between the main and side chains of the growing polymer with the participation of Zn²⁺ ions formed as a result of the transformation of ZnO to ZnCl₂ in the acidic reaction medium of polymerization. The results of the study of the frequency dependences of conductivity indicate a hopping mechanism of conductivity of nanocomposites. The electrical conductivity of nanocomposites depends on their production method and the MWCNT content and varies between 0.5 and 1.1 S∙cm⁻¹, which is 6–12 times higher than the conductivity of the original polymer. Thermogravimetric analysis revealed that the nanocomposites exhibit enhanced thermal stability compared to PCPAB. The best results were shown by nanocomposites with a higher content of MWCNTs, for which the residual mass at 450 °C was 51–53%. Full article

Active antimicrobial films based on polyethylene terephthalate (PET) were developed through atomic layer deposition (ALD) and plasma sputtering to obtain ZnO (≈15 nm) and ZnO/Cu (≈18 nm) coatings. Surface characterization by X-ray photoelectron spectroscopy confirmed zinc in ZnO form and copper as Cu₂O/CuO, while mass spectrometry quantified approximately 10 µg/cm² of Zn in both samples and about 130 ng/cm² of Cu in the ZnO/Cu films. The antimicrobial performance of the coatings was evaluated on burrata cheese and turkey fillets stored under refrigeration, assessing microbial growth and sensory quality over time. The films exhibited different effects depending on food type and the initial contamination levels. On burrata cheese, PET-ZnO moderately extended the shelf life by inhibiting Pseudomonas spp., while PET-ZnO/Cu further enhanced preservation. Cheese packaged with PET-ZnO/Cu remained acceptable for over 21 days compared to 19–20 days for the controls. More pronounced effects were observed in turkey fillets, characterized by a higher initial contamination. In control samples, Staphylococcus spp. rapidly proliferated, leading to spoilage within one day. Both active films significantly delayed microbial growth and sensory decay, with PET-ZnO/Cu providing the best performance, extending acceptability beyond two days compared to less than one day for the controls. Full article

Liquid metal embrittlement (LME) during hot stamping of Zn-coated high-strength steels poses significant challenges to the long-term durability of automotive components. This study investigates how ~30 μm deep LME cracks affect the mechanical behavior of Zn-coated high-strength boron steel. LME-free flat specimens were compared with hat-shaped specimens containing LME cracks. While tensile strength and ductility exhibited minimal changes, the high-cycle fatigue limit (R = −1, 10⁷ cycles) decreased by 10.9% from 550 MPa to 490 MPa in hat-shaped specimens. Fractographic examination revealed distinct stress-dependent crack initiation mechanisms: at high stress amplitudes (≥690 MPa), LME cracks competed with intrinsic substrate defects but did not dominate fatigue failure. In contrast, at moderate-to-low stress amplitudes (≤630 MPa), LME cracks dominated fatigue degradation through a multi-site crack initiation tendency. El Haddad analysis positioned these cracks at the short-to-long crack transition boundary (l ≈ l₀). Preliminary fracture mechanics analysis reveals that conventional single-crack LEFM models systematically overestimate the fatigue threshold stress for LME-affected specimens, a discrepancy qualitatively attributed to the high surface density and morphological complexity of LME crack networks and to chemically assisted grain boundary weakening induced by liquid Zn infiltration—effects not captured by standard fracture mechanics frameworks. These results establish the stress-dependent mechanisms governing LME crack-induced fatigue degradation and provide a mechanistic basis for the development of more accurate fatigue life prediction methods for Zn-coated hot-stamped high-strength steels. Full article

Corrosion resistance of steel wires can be achieved through several approaches, one of the most established being hot-dip galvanizing. The effectiveness of anticorrosive protection of a galvanized wire is considered to depend not only on the galvanizing process itself, namely bath composition, temperature, and immersion duration—but also on the post-galvanizing wiping method, which ultimately determines the final thickness and uniformity of the zinc coating. This study describes and quantifies the resulting parameters of the Zn layer, systematically comparing two technical variants. Four parameters were analyzed to characterize the coating: the effective thickness of the constituent layers, their morphology (examined by SEM), their compositional profile (EDX mapping), and their microhardness. To comprehensively assess the influence of the wiping method on the anticorrosion performance of the galvanized wire, the final corrosion tests, fifth in the sequence, will be conducted in a salt fog environment using an Erichsen chamber, in accordance with standardized procedures. Full article

Zn-Fe-Cr coatings were successfully deposited on sintered Nd-Fe-B matrix through the addition of the complexing agent etidronic acid (HEDP) to the plating solution; the electrodeposited process of the metal elements and the corrosion behavior of the coatings were also investigated. Through cyclic voltammetry (CV) tests, it was observed that the reduction potential difference between the metal elements was reduced by the addition of HEDP, which contributed to a more feasible electrodeposited process. The surface of Zn-Fe-Cr coating was covered by a chromate conversion film, and its microstructure was identified as the solid solution of Fe and Cr in Zn matrix. Compared with Zn and Zn-Fe coatings, the corrosion current density (J_corr) of Zn-Fe-Cr coating was decreased to 0.28 × 10⁻⁶ A·cm⁻², and the corrosion potential (E_corr) was increased to −1.01 V. Compared with the Zn and Zn-Fe coatings, the corrosion rate of the Zn-Fe-Cr coating has decreased by 90% and 98%, respectively. The corrosion resistance of coatings was further analyzed by neutral salt spray tests (NSS), and the analysis results showed that a composite oxide layer, composed of ZnO and Cr₂O₃, was formed in the corroded area of Zn-Fe-Cr coating during the corrosion process, which is capable of effectively inhibiting the expansion of the corrosion area. This research provides a promising strategy for ensuring the long-term service integrity of sintered Nd-Fe-B materials in marine environments. Full article