Decoration Of Ag NPs Research Articles

Facile synthesis of silver nanoparticles loaded spent cathodic Lithium-Ion battery components for enhanced bifunctional photocatalysis: Investigating the influence of magnetic properties

Due to resource depletion and environmental concerns regarding battery disposal, it is becoming more essential to recycle valuable metals from wasted lithium-ion batteries (LIBs). A novel approach is proposed in this study for the efficient bifunctional photocatalysis of LIBs components by integrating AgNPs in an environmentally sustainable manner via a sustainable hydrothermal process. The HRTEM and image mapping reveal a carbon matrix (C/Li3Fe5O8/Ag) with a dispersed arrangement of AgNPs (5–10 wt%). By acting as a reducing agent, graphite plays a crucial role in the transformation of Ag+ ions into AgNPs. The homogenous distribution of Ag NPs observed in the high-resolution TEM images further supports the role of graphite in the modification and decoration of Ag NPs onto the surface of the extracted spent cathode sample. The detection of a spot matching the (200) plane of Ag in the selected area electron diffraction (SAED) measurements confirms the successful formation of AgNPs. Additionally, the presence of a ring corresponding to the (110) plane of graphite in the SAED measurements suggests the coexistence of graphite with AgNPs in the composite heterostructures. The nitrogen adsorption isotherm analysis was conducted to explore the physical properties of the AgNPs@LIBs nanocomposite, providing valuable insights into its pore size distribution and Brunauer–Emmett–Teller (BET) surface area. The nanocomposites exhibited paramagnetic behavior, as revealed by vibrational sample magnetometer (VSM) measurements, with saturation magnetization values ranging from 76.3 × 10−3 to 36.13 × 10−3 emu/g. The study involved the photodegradation of oxytetracycline (OTC), a representative pharmaceutical pollutant, along with an investigation into the potential of Cr(VI) reduction. Under optimal component ratios, a significant improvement in pollutant removal was achieved under UV radiation, reaching up to 75 % for OTC and 80 % for Cr(VI), highlighting the efficiency of the process.

Anticancer effect and laser photostability of ternary graphene oxide/chitosan/silver nanocomposites on various cancer cell lines.

Aims: The development of nanocomposites (NCs) of antitumor activity provides a new paradigm for fighting cancer. Here, a novel NC of green synthetic silver nanoparticles (AgNPs), graphene oxide (GO) and chitosan (Cs) NPs was developed. Materials & methods: The prepared GO/Cs/Ag NCs were analyzed using various techniques. Cytotoxicity of the NCs was evaluated against different cancer cell lines by Sulforhodamine B (SRB) assay. Results: GO/Cs/Ag NCs are novel and highly stable. UV-Vis showedtwo peaks at 227and 469nm, indicating the decoration of AgNPs on the surface of GO/Cs NPs. All tested cell lines were affected by GO/Cs NPs and GO/Cs/Ag NCs. Conclusion: The results indicate that GO/Cs/Ag NCswere presenton tested cell lines and area promising candidate for cancer therapy.

A TiO2 nanotube array decorated by Ag nanoparticles for highly sensitive SERS determination and self-cleaning of vitamin B12

The Ag-deposited TiO2 nanotube arrays (TNTA/Ag) are prepared via the decoration of Ag nanoparticles (Ag NPs) on an anodized TiO2 nanotube. Descriptive physicochemical features of prepared probes were studied by XRD, FESEM, and RAMAN analyses to prove the successful construction of ordered TNTA and decoration of Ag NPs over them. A highly appropriate and efficient determination method based on surface-enhanced Raman spectroscopy (SERS) has been developed using TNTA/Ag probe for vitamin B12 detection. The results displayed that the TNTA/Ag probe has superior detection sensitivity with detection limit of as low as 2.48 × 10−8 M and high reproducibility of different spots on the probe surface with a relative standard deviation of 9.69 %. Moreover, the prepared probe could clean itself due to the photocatalytic ability of TiO2 and surface plasmon resonance effect (SPR) of Ag NPs to be repeatedly used as a SERS probe. The reliability of TNTA/Ag SERS probe was affirmed further by the detection of vitamin B12 in real pharmaceutical samples.

Construction of Ag-decorated ZnO with oxygen vacancies for enhanced antibacterial activity via increased H2O2 production

Ag-decorated ZnO nanorods with different Ag contents were prepared by deposition-precipitation method, which demonstrated enhanced inhibition ability for the common pathogen, especially exhibited excellent antibacterial effects on clinical drug resistant bacteria. Moreover, Ag-decorated ZnO nanorods presented much lower cytotoxicity to HEK293 cell than that of silver nanoparticles (AgNPs). The electron spin resonance (ESR) spectra revealed that oxygen vacancies (VO) were formed in ZnO after the decoration of AgNPs. To understand the improved antibacterial activity of Ag-decorated ZnO nanorods, reactive oxygen species (ROS) were determined. It was found that more H2O2 were generated over Ag-decorated ZnO compared to pure ZnO, which was closely related to the oxygen vacancy (VO) concentration. The production of large amount of H2O2 resulted in more serious membrane leakage of cytosol and dehydrogenation inactivation of respiratory chain for bacterial, thus leading to the enhanced antibacterial activities of Ag-decorated ZnO nanorods.

Synthesis of Ag Nanoparticles-Decorated CNTs via Laser Ablation Method for the Enhancement the Photocatalytic Removal of Naphthalene from Water.

Silver nanoparticles (Ag NPs) were decorated with different amounts on the exterior walls of carbon nanotubes (CNTs) by a laser ablation assisted method, especially in liquid media to be applied as a good adsorption material against naphthalene. The laser ablation time was controlled the amount of decoration Ag NPs on CNTs. The prepared nanocomposite was analyzed via different analytical techniques. Ag NPs with a small size distribution of 29 nm are uniformly decorated with spherical shape on CNTs walls. The disorder degree of tubular structure and shifting of the vibrational characteristic peaks increase with the increase in the decoration of Ag NPs. After that, the prepared samples were investigated for the removal of naphthalene. These studies of loading Ag NPs with different amounts on the surface of CNTs act as a promising material for water treatment.

Silver nanoparticles decorated phthalocyanine doped polyaniline for the simultaneous electrochemical detection of hydroquinone and catechol

Abstract In this proposed study, the new electrocatalyst was synthesized by incorporating the supramolecular electrocatalyst tetra amino cobalt phthalocyanine (TACoPc) into the conducting polyaniline (PANI) and which was subsequently used to decorate silver nanoparticles (AgNPs) using Ag+ solution on the surface of TACoPc/PANI composite to form a supramolecular hybrid system. The decoration of AgNPs on the surface of TACoPc/PANI was carried out in an aqueous media at room temperature and which was confirmed by various spectroscopic techniques. The synthesized catalyst AgNPs decorated TACoPc doped PANI (TACoPc/PANI/AgNPs) modified the glassy carbon electrode (GCE) used to construct the electrochemical sensor for simultaneous detection of hydroquinone (HQ) and catechol (CC). The modified electrode showed the two distinct peaks for HQ and CC in CV analysis with a considerable potential difference of 0.080 V vs SHE. The presence of central cobalt metal in TACoPc macromolecular electrocatalyst mediates the oxidation of HQ and CC, which was successively enhanced by the incorporation of conducting PANI and AgNPs. The sensor exhibited excellent electrocatalytic activity with good stability, selectivity, reproducibility, and a very low limit of detection in the electrochemical sensing of HQ and CC in a 0.1 M H2SO4 electrolyte solution.

Synthesis and characterization of silver nanoparticle-decorated cobalt nanocomposites (Co@AgNPs) and their density-dependent antibacterial activity.

Magnetic cores loaded with metallic nanoparticles can be promising nano-carriers for successful drug delivery at infectious sites. We report fabrication, characteristic analysis and in vitro antibacterial performance of nanocomposites comprising cobalt cores (Co-cores) functionalized with a varied concentration of silver nanoparticles (AgNPs). A two-step polyol process synchronized with the transmetalation reduction method was used. Co-cores were synthesized with cobalt acetate, and decoration of AgNPs was carried out with silver acetate. The density of AgNPs was varied by changing the amount of silver content as 0.01, 0.1 and 0.2 g in the synthesis solution. Both AgNPs and Co-cores were spherical having a size range of 30–80 nm and 200 nm to more than 1 µm, respectively, as determined by scanning electron microscopy. The metallic nature and face-centred cubic crystalline phase of prepared nanocomposites were confirmed by X-ray diffraction. Biocompatibility analysis confirmed high cell viability of MCF7 at low concentrations of tested particles. The antibacterial performance of nanocomposites (Co@AgNPs) against Escherichia coli and Bacillus subtilis was found to be AgNPs density-dependent, and nanocomposites with the highest AgNPs density exhibited the maximum bactericidal efficacy. We therefore propose that Co@AgNPs as effective drug containers for various biomedical applications.

Visible light enhancement of ammonia detection using silver nanoparticles decorated on reduced graphene oxide

A novel NH3 gas sensor based on reduced graphene oxide sheets (rGO) with uniformly decorated silver nanoparticles (AgNPs) on its surface is presented in this work. The aqueous solution containing silver nitrate, gelatin and graphene oxide (GO) is exposed to acoustic energy to reduce the silver nanoparticle on rGO sheets. FESEM image and EDX spot analysis show that an ultrafine spherical AgNPs with the size of about 20–30 nm are uniformly distributed on the rGO sheets. Small Raman shift of centered peaks at 1960 cm−1 indicate the decoration of AgNPs on rGO. The UV–vis absorption peaks show a red shift toward visible spectrum from 267 nm for rGO to 459 nm for rGO decorated with AgNPs. The AgNPs/rGO nano composite as an active layer over the Cr/gold interdigited electrode is fabricated using lithography technique and are tested using a semi-automatic static set up. The sensitivity of the AgNPs/rGO is about 5.8 for 250 ppb of NH3 gas detection. While this sensor shows reproducible, stable and fully recoverable response, its limit of detection (LOD) for NH3 gas is 100 ppt. The response and recovery times are 76 and 84 s respectively. The sensor exhibits an even better sensitivity of about 1.7 times for ammonium gas detection at room temperature when it is expose to visible light of 10 mW cm−2 (blue LED) which is believed to be due to the surface plasmon resonance (SPR) and spillover effects.

In situ decoration of silver nanoparticles on single-walled carbon nanotubes by microwave irradiation for enhanced and durable anti-bacterial finishing on cotton fabric

Present communication reports microwave-assisted process to decorate single-walled carbon nanotubes (SWCNTs) with silver nanoparticles (Ag-NPs) to induce excellent and durable anti-bacterial activity in cotton fabric. Pristine SWCNTs were functionalized (f-SWCNTs) through acidic treatment for nucleation, followed by reduction of silver ion by microwave heating to produce Ag-NPs decorated SWCNTs (Ag-SWCNTs). Functionalization and decoration of Ag-NPs on SWCNTs were characterized by FTIR, XRD, RAMAN spectroscopy and FE-SEM. Microwave irradiation time was optimized and it was observed that complete reduction of Ag ions on SWCNTs from its precursor (AgNO3) took place within 40 s of microwave irradiation time. For antibacterial activity measurement and comparison, pristine SWCNTs, Ag-NPs and Ag-SWCNTs composite were individually coated on different cotton fabrics via dip-dry-curing process. Deposition of these particles on cotton fabrics were confirmed by FE-SEM and Raman spectroscopy. Antibacterial property of all coated fabrics was evaluated qualitatively against Staphylococcus aureus (S. aureus) as gram positive and Escherichia coli (E.coli) as gram negative pathogenic bacteria. It was observed that the fabric coated with Ag-SWCNTs show excellent antibacterial activity against both types of bacteria. Sufficient antibacterial activity of Ag-SWCNTs coated fabrics was observed even after 20 washing.

Reduced graphene oxide-silver nanoparticles/nitrogen-doped carbon nanofiber composites with meso-microporous structure for high-performance symmetric supercapacitor application

The electrochemical performance of carbon nanofibers (CNFs) as the electrode material of the supercapacitor should be improved to meet requirements of renewable energy systems. We report here the synthesis of nitrogen-doped carbon nanofibers (RGO-AgNP/N-CNF) with a meso-microporous structure by the supplement of reduced graphene oxide–silver nanoparticles (RGO-AgNPs) into N-CNFs. The usage of polyacrylonitrile (PAN) is aimed to supply nitrogen doped in carbon bulk, which can enhance fast migration of electrolyte ions during the electrochemical process. Decoration of AgNPs on RGO surface improves electrical conductivity of RGO-AgNP/N-CNF composites and alleviates the aggregation of AgNPs. The addition of RGO-AgNPs elevates the specific surface area and mesoporous content of CNFs. The assembled RGO-AgNP/N-CNF symmetric supercapacitor possesses high specific capacitance of 188.0 F g−1 at a current density of 0.5 A g−1, delivers an ultrahigh energy density of 26.1 Wh kg−1 and displays an excellent cycling performance (97.5% retention after 5000 cycles), which suggest its big potential as energy storage devices.

Strong enhancement of electrical conductivity in two-dimensional micrometer-sized RuO2 nanosheets for flexible transparent electrodes.

The enhancement in electrical transport properties of exfoliated individual RuO2 NSs was systemically investigated for their application in flexible electronics and optoelectronics. Decoration of Ag NPs on the surface of the RuO2 NSs provides donor electrons and dramatically increases the electrical conductivity of the monolayer RuO2 NSs by up to 3700%. The n-type doping behavior was confirmed via Hall measurement analysis of the doped RuO2 NSs. The layer number- and temperature-dependence of the conductivity were also investigated. Moreover, carrier concentration and mobility were obtained from Hall measurements, indicating that the undoped RuO2 NSs had ambipolar transport and semi-metallic characteristics. Moreover, the Ag-doped RuO2 NS multilayer films on polycarbonate substrates were demonstrated by the Langmuir-Blodgett assembly methods, showing one-third reduction in the sheet resistance and extraordinarily high bending stability that the change in the resistance was less than 1% over 50 000 cycles.

Three-Dimensional Surface-Enhanced Raman Scattering Substrate Fabricated Using Chemical Decoration of Silver Nanoparticles on Electrospun Polycarbonate Nanofibers.

In this work, a simple method via decoration of silver nanoparticles (AgNPs) on electrospun polycarbonate nanofibers (PCNFs) was proposed to prepare highly sensitive three-dimensional (3D) substrates for surface-enhanced Raman scattering (SERS) measurements. The method proposed in this work gave a high sensitive Ag@PCNFs substrate, which resulted from a successful production of high surface area of PCNFs with a high efficiency in the decoration of AgNPs. To produce PCNFs suitable for SERS application, parameters in fabrication of PCNFs were systematically examined and correlated with their corresponding scanning electron microscope (SEM) images. Examined parameters included the concentration of PC solution, the solvent to form PC solution, the applied voltage, and the rotating speed of a drum collector. Using the optimized condition, the bead-free PCNFs with a diameter in the range of 200-400 nm were successfully produced. To increase the efficiency in decoration of AgNPs, the surface properties of PNCFs were altered with an organic solvent, which was selected experimentally with guidance of Hildebrand solubility parameter. Results indicated that methanol was the most suitable solvent to effectively decorate AgNPs on PCNFs. By probing with para-hydroxythiophenol (pHTP), prepared SERS substrates of Ag@PCNFs provided an enhancement factor to the order of 7, which is at least an order of magnitude larger than the reported values in the literature for SERS substrates prepared with the electrospinning technique.

Synergistic antibacterial activity of PEGylated silver–graphene quantum dots nanocomposites

The emergence of antibiotic-resistant bacteria is a major threat to world-wide public health. Functionalized nanoparticles could offer novel strategies in this post-antibiotic era. In this study, we developed nanocomposites of silver nanoparticles decorated with graphene quantum dots (Ag-GQDs) using pulsed laser synthesis. The nanocomposites were PEGylated, which increases their biocompatibility and solubility in aqueous solutions. The HR-TEM micrographs of bare GQDs show that their size is in the range of 1.6–4nm, and the lattice spacing is 0.214nm, which corresponds to the (100) lattice fringes of graphene. The antibacterial activity of Ag-GQDs was evaluated and compared to that of bare GQDs and commercial silver nanoparticles (Ag-NPs) against both Gram-negative and Gram-positive bacteria, using Pseudomonas aeruginosa and Staphylococcus aureus as model bacteria, respectively. Concentration values of 25 and 50μg/mL are required for Ag-GQDs to inhibit the growth of S. aureus and P. aeruginosa bacteria, respectively. The fractional inhibitory concentration (FIC) index is below 0.5 indicating that there is a synergistic effect between Ag-NPs and GQDs. Kirby–Bauer tests showed that Ag-GQDs inhibit P. aeruginosa and S. aureus, in contrast to bare GQDs and Ag-NPs alone. Cell viability of normal mammalian cells treated with Ag-GQDs showed that cell viability is maintained at 100% for cells incubated with Ag-GQDs. The decoration of Ag-NPs with GQDs minimizes their cytotoxicity in mammalian cells and increases their biocompatibility. Ag-GQDs have potential applications in the fabrication of antibacterial coatings, self-sterile textiles, and personal care products.

Facile Synthesis of Silver Nanoparticles Decorated Magnetic-Chitosan Microsphere for Efficient Removal of Dyes and Microbial Contaminants

A facile and rapid synthesis of core–shell type magnetite-chitosan microsphere decorated with silver nanoparticles (MCSM) is described. The composition and structure of the as-synthesized microsphere characterized by various spectroscopic and microscopic techniques demonstrated formation of 3.63 ± 0.76 μm MCSM with decoration of silver nanoparticles (AgNPs) having 16 ± 2.5 nm size. The thermogravimetric analysis (TGA) data showed good thermal stability, whereas vibrating sample magnetometry (VSM) analysis indicated the superparamagnetic behavior of the as-synthesized microsphere. The adsorptive removal and antimicrobial property of MCSM was explored for eco-friendly and cost-effective water purification. The MCSM removed 99.99% microbial contaminants and 99.5% of dyes from single as well as multicomponent systems from water bodies efficiently. Furthermore, the dye removal capacity of MCSM (qe = 271.2 ± 14.5 mg/g) was found to be higher compared to the other nanoadsorbents attributing to the high effective surface area of the microsphere and plenty of functional groups of shell structure of chitosan favored binding of dyes on MCSM. Moreover, the adsorbed dyes were desorbed from MCSM at higher pH values and regenerated MCSM was used for next cycle of dye removal. The magnetic behavior of MCSM facilitated easy separation using external magnetic field leading to recycling and reuse, whereas decoration of AgNPs on the microsphere inhibited the bacterial growth. The long-term antibacterial activity of MCSM significantly improved the antifouling property to inhibit the biofilm formation on MCSM. The proposed core–shell type MCSM thus provides a promising opportunity for cost-effective water purification.

Treatment Effects of ZnO and Al:ZnO Photoanodes on Short-Circuit Photocurrent and Open-Circuit Photovoltage of Quantum Dot Sensitized Solar Cell Using Ag Nanoparticles

This study investigates the treatment effects of ZnO and Al:ZnO (AZO) photoanodes on short-circuit photocurrent (Jsc) and open-circuit photovoltage (Voc) of quantum dot sensitized solar cell using Ag nanoparticles (Ag NPs). Current density-voltage (J–V) characterization showed that Jsc of QDSSC rises for treated ZnO photoanode with Ag NPs, whereas it decreases in AZO/Ag NPs photoanode based QDSSCs. Also, it was found that Voc raises when treating both ZnO and AZO photoanodes of QDSSCs with Ag NPs. These results were studied using electrochemical impedance spectroscopy (EIS) and absorption spectra. EIS results indicated that recombination resistance of photoanode/electrolyte interfaces of QDSSC increases with decoration of Ag NPs on ZnO and AZO photoanodes which, consequently, results in reduction of electron back into electrolyte. Furthermore, it was observed that chemical capacitance of photoanode enhances with treatment of ZnO photoanode, while being extremely reduced for AZO photoanode.

Synthesis of silver nanoparticles on reduced graphene oxide under microwave irradiation with starch as an ideal reductant and stabilizer

A facile aqueous solution procedure has been developed to synthesize silver nanoparticles (Ag NPs) on reduced graphene oxide (RGO) (RGO/Ag NPs) with starch as an ideal reductant and stabilizer in one pot under microwave irradiation. Graphene oxide and Ag(NH3)2+ were reduced simultaneously by starch in the process of forming Ag NPs. The size of Ag NPs decorated on the RGO sheets is about 20–50nm and the average size of Ag NPs on RGO is 34nm calculated by X-ray diffraction. RGO and RGO/Ag NPs prepared with starch show good stability in aqueous solution. With the decoration of Ag NPs on RGO, Raman intensity of RGO increased evidently. Antimicrobial activity of RGO/Ag NPs was investigated against the gram negative bacteria Pseudomonous aeruginosa. The minimum inhibitory concentration (MIC) of RGO/Ag NPs is 0.2wt%. The antimicrobial activity of RGO/Ag NPs is stronger than Ag NPs because of the synergic effect of RGO and Ag NPs.