Plant-mediated synthesis provides a sustainable approach for producing multifunctional nanomaterials. In this study, silver nanoparticles (Ag NPs), magnesium oxide nanoparticles (MgO NPs), and an Ag/MgO nanocomposite (Ag/MgO NCs) were synthesized using Salvia rosmarinus leaf extract and comparatively evaluated. GC–MS and HPLC analyses identified terpenoids, phenolic acids, and flavonoids that may contribute to nanomaterial formation and stabilization. The synthesized materials were characterized using UV–Vis, FTIR, XRD, SEM, TEM, HR-TEM, SAED, EDX mapping, DLS, zeta-potential, TGA/DTG, and nitrogen adsorption–desorption analyses. HR-TEM showed adjacent crystalline domains with lattice spacings of approximately 0.24 and 0.23 nm, tentatively assigned to MgO(111) and Ag(111), respectively, while SAED supported the polycrystalline nature and coexistence of Ag- and MgO-containing domains. Ag/MgO NCs exhibited a TEM-derived particle size of 66.86 ± 28.72 nm, a hydrodynamic diameter of 95.32 nm, a PDI of 0.339, and a zeta potential of −36.4 mV. Ag/MgO NCs exhibited greater antibacterial activity than the individual nanoparticles against Salmonella typhi, Staphylococcus aureus, Enterococcus faecalis, and Klebsiella pneumoniae, producing inhibition-zone diameters of 15–27 mm and MIC values of 62.5–250 μg/mL. TEM observations and increased extracellular protein leakage supported bacterial membrane damage, while biofilm inhibition reached 56.46 % against S. aureus and 61.52 % against K. pneumoniae. Ag/MgO NCs exhibited IC50 values of 152.37 and 444.23 μg/mL against HeLa and non-cancerous Vero cells, respectively, corresponding to borderline-to-moderate preferential cytotoxicity toward HeLa cells (SI = 2.91). Flow cytometry demonstrated 33.5 % total apoptosis and an increase in the S-phase population from 4.3 % to 32.5 %. The nanocomposite also exhibited improved DPPH and ABTS radical-scavenging activities, with IC50 values of 140.23 and 275.90 μg/mL, respectively, and inhibited α-amylase and α-glucosidase with IC50 values of 358.5 and 102.76 μg/mL. Overall, Ag/MgO NCs displayed improved multifunctional biological performance relative to Ag NPs and MgO NPs; however, further mechanistic, biosafety, and in vivo studies are required.
Nanoparticle-reinforced hybrid composites have attracted considerable attention for lightweight structural applications owing to their superior mechanical performance and impact resistance. This study investigates the influence of reduced graphene oxide (rGO) on the mechanical, ballistic, dynamic, and microstructural behaviour of Kevlar–Basalt/epoxy hybrid composite laminates fabricated using the hand lay-up technique. Four laminates containing 0, 0.1, 0.2, and 0.3 wt% rGO were evaluated through tensile, compression, flexural, ballistic, free vibration, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses. The laminate containing 0.2 wt% rGO exhibited the optimum quasi-static mechanical and dynamic performance, with improvements of 7.8 % in tensile strength, 70.2 % in compressive strength, and 24.6 % in flexural strength compared with the neat laminate. In contrast, the laminate reinforced with 0.3 wt% rGO demonstrated superior ballistic performance, increasing the energy absorption from 39.94 % to 84.01 %, while reducing the residual projectile velocity from 93.0 m/s to 47.98 m/s and the damaged area from 368.21 mm2 to 276.48 mm2. Free vibration analysis confirmed improved dynamic stiffness at the optimum rGO loading. SEM analysis revealed progressive improvements in fracture morphology and crack propagation behaviour, while XRD and FTIR confirmed that rGO incorporation preserved the fundamental structural and chemical characteristics of the hybrid laminates. These findings demonstrate that the incorporation of an optimum rGO concentration enhances the multifunctional performance of Kevlar–Basalt hybrid composites, highlighting their potential for lightweight structural and protective applications.
Ammonia (NH3) volatilization is a major pathway of reactive nitrogen loss, making accurate and real-time NH3 monitoring essential for improving nitrogen-use efficiency and mitigating environmental impacts. Herein, a room-temperature chemiresistive NH3 sensor based on a PANI/SnS2 p–n heterojunction composite is developed for real-time ammonia monitoring. The composite was synthesized via in situ chemical oxidative polymerization and deposited onto flexible Au interdigital electrodes. Structural characterization confirms the successful integration of PANI and SnS2 and the formation of closely contacted heterojunction interfaces. The optimized composite exhibits a response of 959.7 % toward 100 ppm NH3 and a sensitivity of 9.85 % ppm−1 at room temperature. In addition, the sensor demonstrated stable sensing performance over a 10-day laboratory test, and excellent selectivity, with negligible responses to common interfering gases. The enhanced sensing performance was attributed to the synergistic effects of the PANI/SnS2 heterojunction and the NH3-induced deprotonation of PANI. Soil volatilization and paddy-field experiments further demonstrated the potential of the sensor for real-time NH3 monitoring under practical conditions.
This manuscript reports the synthesis and multifunctional characterization of cobalt-zinc oxide (Co-ZnO) nanoparticles prepared by room-temperature co-precipitation followed by calcination at 400 °C. X-ray diffraction (XRD) confirmed a dominant hexagonal wurtzite ZnO framework with an average crystallite size of 13.4 ± 0.8 nm and weak cobalt-oxide-related contributions. High-resolution FESEM and TEM revealed aggregated quasi-spherical nanoparticles; re-analysis of 19 clearly resolvable TEM features gave an equivalent projected diameter of 12.2 ± 3.0 nm. Fitted XPS spectra confirmed Zn2+ and Co2+-containing environments and resolved lattice, defect-/hydroxyl-associated, and surface-adsorbed oxygen components, with an estimated surface Co/Zn atomic ratio of 0.42. UV–Vis analysis using a direct-allowed Tauc representation gave an apparent optical band gap of approximately 2.10 eV. Magnetic measurements indicated dominant paramagnetic behaviour at 300 K with a weak ferromagnetic contribution and a stronger response at 10 K. Electrochemical evaluation showed a CV-derived specific capacitance of 13.36 ± 0.42 F g−1 at 0.01 V s−1 and a GCD-derived capacitance of 1.57 ± 0.08 F g−1, both exceeding the corresponding pure-ZnO control under identical conditions. Cycling tests showed 90.1 % capacitance retention after 3,000 cycles and an average coulombic efficiency of 98.4 %. These results show that Co incorporation modifies the structural, optical, magnetic, and electrochemical response of ZnO while retaining stable, moderate charge-storage behaviour.
Graphene-like two-dimensional material sensors are rapidly advancing toward intelligence and sustainability. This article reviews the latest progress in external field regulation and green manufacturing processes, with a focus on their synergistic integration pathways. In terms of external field regulation, photoelectric synergy lowers the NO2 detection limit to 10 ppb and shortens the humidity response time to 1 s; electrical regulation enables mid-infrared polarimeters and high-sensitivity plasmonic sensing; magnetic regulation endows germanene and silicene with tunable magneto-optical responses. In terms of green manufacturing, strategies such as using cork, silk fibroin, Cyrene solvent, and electrochemical exfoliation achieve low-energy, pollution-free fabrication, which have been successfully applied to glucose, pressure, and gas sensing. However, current research on these two major directions remains independent, facing challenges such as low electrical conductivity of green materials, random defects, energy compensation by external fields, and poor batch-to-batch consistency. In the future, it is necessary to establish a closed-loop “process–material–performance” design, develop controllable defect engineering and low-power regulation modes, advance multi-material heterointegration and sensing–memory–computing integration, and ultimately realize high-performance, scalable, and environmentally friendly intelligent sensing systems.
