Papers by Keyword: Silver

Abstract: Ag@TiO₂ core-shell nanoparticles (NPs) were synthesized through an environmentally benign, two-step method utilizing Aloe vera extract as a natural reducing and capping agent. Structural and morphological characterization via X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) confirmed the successful formation of spherical core-shell structures with a size range of 10-40 nm. Optical analysis revealed a wide bandgap of 4.8 eV, indicative of quantum confinement effects. While electrokinetic measurements suggested moderate colloidal stability (zeta potential near 0 mV), the nanoparticles exhibited potent, strain-dependent antimicrobial activity. Notably, they demonstrated superior efficacy against Gram-positive Staphylococcus epidermidis (32 mm inhibition zone) compared to Gram-negative Escherichia coli (21 mm inhibition zone). This green synthesis route presents a sustainable strategy for producing antibacterial nanoparticles with enhanced activity against Gram-positive pathogens.

Abstract: This research investigated the impact of Ag content supported on ZnO catalysts regarding the oxidation activity of DPM. The catalyst was synthesised through the doping of varying Ag concentrations on ZnO (e.g., 2, 4, 8, and 16 wt%) employing the incipient wetness impregnation technique. Characterisation of the synthesised catalyst was conducted utilising XRD, SEM, TEM, and H₂-TPR. The evaluation of oxidation activity and stability was performed through TGA. The characterisation findings substantiated the successful integration of Ag onto ZnO across all experimental conditions investigated. H₂-TPR profiles revealed two distinct regions of H₂ consumption: 1) at 200-400 °C, and 2) at 400-700 °C. These regions were attributed to the reduction of Ag₂O to Ag⁰ and the liberation of lattice oxygen from ZnO, respectively. An increase in Ag concentrations resulted in enhanced reduction reactions within the temperature spectrum of 400 to 700 °C, demonstrating a favourable trend towards improved reaction efficiency. The oxidation performance of DPM was markedly augmented by the Ag content, particularly at 16 wt%. Stability assessments indicated a consistent capability in facilitating DPM oxidation across five cycles. The concentration of oxygen exhibited a significant influence on the oxidation activity of DPM.

Abstract: The high-voltage application to silver ion-doped borosilicate glass induces the growth of silver dendritic crystals precipitation inside the substrate. This phenomenon holds significant potential for applications such as buried electric circuits and fine-hole drilling. Therefore, understanding the underlying mechanism of this phenomenon is essential for its practical utilization. In this study, we conducted in-situ observation and quantitative evaluation of the silver dendrite growth based on the temperature and the precipitation area over time. The measurements revealed that the growth rate accelerated as the precipitation progressed and increased with higher temperatures. Moreover, a model proposed here explained that these changes were attributed to the variations in the electrical resistance of the specimens and difference in the flux of the silver ions. This study provides valuable insights into the mechanism of silver dendritic precipitate growth inside glass, enabling the formation of arbitrary shapes of in-glass silver.

Abstract: Inherent magnetic features of engineered nanoparticles are quite important parameters for biomedical application. In this study, trying to process Bengawan Solo iron sand into a material that has potential for cobalt ferrite (CFO-NPs) and silver-cobalt ferrite (AgCFO-NPs) were synthesized by aqueous extract of tumeric. To modify the physical properties, annealing treatment was carried out at non-annealing temperatures and 500°C. The characterized by various instrument, and utilized for biomedical application with antibacterial activity. These are characterized XRD with showing results particle size was calculated by the Scherrer formula, which is around 19 nm to 25 nm. The results of FTIR peak adsorption at 400 and 600 cm^-1 it shows the characteristics of spinel ferrite and the presence of vibrations at tetrahedral and octahedral sites. The coerciveness field (Hc) while those subjected to annealing temperature treatment increased from 46 Oe to 136 Oe. Nanoparticles cobalt ferrite (CFO-NPs) and silver-cobalt ferrite (AgCFO-NPs) can be used as antibacterial application. The AgCFO-NPs material has an antibacterial function as seen in the antibacterial test. AgCFO-NPs showed a good response being able to inhibit the growth of Staphylococcus aureus and Eschericia coli bacteria. By the obtained result it can be claimed that material nanoparticles will be useful model for biomedical applications if they are explored at advance level.

Abstract: This paper presents the synthesis of metallic silver (Ag) nanoparticles immobilized on silica (SiO₂) particles. Ag immobilization was carried out via the Ag mirror reaction using two types of reducing reagents: D-glucose and formaldehyde (HCHO). The effects of Ag immobilization conditions, such as Ag nitrate concentration, SiO₂ concentration, reaction time, and reducing reagent concentration, were investigated. The particle morphology is related to the ionic strength of the solution. As a result, Ag immobilization was successfully performed while minimizing the formation of large metallic Ag nanoparticles and/or the aggregation of metallic Ag nanoparticles in the HCHO system with a reaction time of 5 min and HCHO concentration of 1.5×10^-4 M, producing SiO₂ particles (92.5±7.3 nm) immobilized with metallic Ag nanoparticles 5–15 nm in size.

Abstract: The mesoporous silica nanoparticle (MSN) is a material with easily controllable pore size and excellent surface area to develop into a corrosion inhibitor nanocarrier, a protective coating specially produced by a nanocomposite layer to keep or release anticorrosive active compounds. Nonetheless, the MSN is not weakness-free, which cannot impede corrosion propagation actively. Special treatment for overcoming is developing the benzotriazole-silver (BTA-Ag)-based capping system, with advantages that can exploit the double anticorrosive mechanism by adjusting anticorrosive active compound release while capturing chloride ions, leading to active self-healing. Therefore, this work identifies the effect of developing a capping system based on BTA-Ag on the porosity properties of MSN as an initial step in preparing corrosion inhibitor nanocarrier. Rice husks were chosen as eco-friendly materials to replace commercial precursors because of their abundance, the same orthosilicate structure, and the high purity of silica. With excellent levels of safety and uniformity, this work uses the sol-gel method to reduce the synthesis energy or cost. The outcome indicates that the porosity characteristics of these nanoparticles are significantly impacted by the BTA-Ag-based capping method. The pore size shrank to 2.5 nm from 2.6 nm. Additionally, the surface area decreased dramatically from 653.149 to 41.725 m²/g. Moreover, the pore volume dropped from 0.9 to 0.1 cm³/g. However, it had a comparable morphology, varied in size, and a specific aggregation level, indicating the presence of densely packed rod-like micelles during the MSN synthesis. The sample was confirmed to be porous since the isotherm graph was of type IV. It was highly reactive due to silanol and siloxane groups, signaling bonds with the silica matrix being the main component.

Abstract: Silver nanoparticles (AgNPs) have attracted attention due to their unique properties and potential application. This research aimed to do green synthesis of AgNPs with Syzygium aromaticum leaves extract (SALE) and evaluate their antibacterial and antioxidant activities. Syzygium aromaticum leaves were extracted using distilled water at 70 °C for 30 min and the results were characterized with FTIR. AgNPs were synthesized by mixing AgNO₃ precursor with SALE. The effects of parameters such as volume ratio of AgNO₃ precursor to SALE, AgNO₃ concentrations, and synthesis times were investigated. The synthesized AgNPs were characterized using UV-Vis spectrophotometer, FTIR, and TEM. Antibacterial activity of SALE and AgNPs was investigated against Escherichia coli (E.coli) and Bacillus subtilis (B. subtilis) with disc diffusion method and antioxidant activity was tested with DPPH method. The FTIR characterization revealed that SALE and resulting AgNPs contain O-H, C-H, C=O, C=C, C-O, and C≡C functional groups. The UV-Vis characterization demonstrated that AgNPs exhibited an absorption peak at λ = 420 nm indicating surface plasmon resonance. The optimal volume ratio of AgNO₃ to SALE, AgNO₃ concentrations, and synthesis time for AgNPs synthesis was achieved at 10:3, 5 mM, and 60 min respectively. TEM characterization indicated that AgNPs have spherical form and sizes ranging from 14 to 32 nm. The antibacterial testing revealed that AgNPs have antibacterial activities against E. coli and B. subtilis with inhibition zone values are 8,38 ± 0,48 and 6,88 ± 1,47 respectively. Additionally, antioxidant testing presented that the IC₅₀ values were 85.05 µg/mL for SALE and 34.71 µg/mL for AgNPs. The results indicate that green synthesis of AgNPs from AgNO₃ precursor with SALE was done successfully and this nanoparticle has good antibacterial and antioxidant activities.

Abstract: Conductive inks composed of chemically sintered silver (Ag) nanoparticles were prepared. The enlargement of particle size was accompanied by the increase in conductivity of the Ag nanoparticle ink. The resistance of the as-prepared and sintered Ag nanoparticles printed on different substrates was measured, and results showed that the formulated conductive ink works best on glossy paper. This is due to the compatibility of the conductive ink with the porosity and surface roughness of the glossy paper. The conductive ink formulation was also used as printer ink, and results showed a decrease in resistance as the printing pass was increased.

Abstract: Recently, copper (Cu) and silver (Ag) nanowires have been widely employed as conductive fillers in flexible electronic devices due to their high aspect ratios leading to the formation of conductive networks in a polymeric substrate. This study combined Cu and Ag as a 1-dimensional nanostructures through galvanic replacement with a core-shell configuration. The effects of the galvanic replacement factors on the Cu-Ag core-shell nanostructures morphology was studied by varying the reaction time, temperature, and Ag concentration. SEM images show a more extensive Cu dealloying and Kirkendall voiding with longer reaction times, resulting in the Cu core dissolution. Homogenous nucleation of Ag occurs at higher reaction temperatures and Ag concentrations, producing separate Ag particles.

Abstract: Herein, we report for the first time the thermal diffusivity of zinc ferrite/ silver/ silver chloride nanocomposite with a four-fold enhancement in comparison with the base fluid. A systematic analysis of the dependence of calcination temperature and synthesis routes on the crystallinity of nanocomposites of zinc ferrite with silver and silver chloride suiting it for diverse applications was done. Synthesized via the co-precipitation method, the samples were characterized using X-ray diffraction, Field emission scanning electron microscopy, Energy dispersive X-ray, Vibration sample magnetometer, ultraviolet-visible Diffusive Reflective spectroscopy and Photoluminescence studies. A zeta potential of -31.1mV was obtained for the sample showing good colloidal stability. The thermal diffusivity of the samples as nanofluids was analyzed using the dual beam thermal lens method. The study also envisages the magnetically retrievable and visible light-active nature of the synthesized samples indicating their suitability for photocatalytic degradation of toxic dyes. The work on photocatalytic degradation of methylene blue stands out in attaining rapid, efficient dye degradation of 98% within 90 minutes of sunlight exposure in comparison with unblended zinc ferrite nanoparticles even without any oxidizing agent.