Deposition Of Ag Nanoparticles Research Articles

Enhanced photocatalytic activity of Ag/ZnO nanocomposite immobilized on kanthal coils

Constructing hybrid semiconductor photocatalysts and increasing the charge-carrier density are effective strategies for enhancing the photocatalytic performance of ZnO. This study elucidates the synergistic effects of electron trapping and surface plasmon resonance (SPR) on the activity of ZnO photocatalysts. Ag/ZnO nanocomposites were synthesized on Kanthal coils using a two-step method involving the immobilization of ZnO on Kanthal coils and the coupling of Ag nanoparticles. XPS and RTPL analyses verified the synergistic effects of electron trapping and SPR on the activity of the Ag/ZnO nanocomposites. The photocatalytic performance of the composite was evaluated in the degradation of rhodamine B (RhB) dye. The Ag/ZnO nanocomposite exhibited significantly enhanced removal efficiency for RhB dye (38.2–70.5% depending on the deposition time). The Ohmic contact at the Ag/ZnO heterojunction extended the lifetime of the photoinduced charge carriers, whereas the SPR facilitated the generation of more electrons for the photocatalytic reaction. However, the excessive deposition of Ag nanoparticles compromised the photocatalytic performance of the Ag/ZnO nanocomposite. This study provides valuable insights for developing efficient ZnO-based photocatalytic materials for addressing environmental challenges.

Fast and scalable fabrication of Ag/TiO2 nanostructured substrates for enhanced plasmonic sensing and photocatalytic applications

Here we propose a fast and scalable (up to 3 min for 6 × 1 cm size substrate) innovative approach to fabricate coral-shaped TiO2 nanostructured substrates based on thermal oxidation of titanium foil followed by deposition of Ag nanoparticles for bifunctional sensing and photocatalysis. Comprehensive studies on the morphology, crystal structure, stoichiometry, optical, and electronic properties of these nanostructures reveal the formation of a Schottky barrier at the Ag/TiO2 interface. This interface alters the electronic structure of the Ag/TiO2 nanosystem, retaining the plasmonic properties of Ag nanoparticles while enhancing their catalytic activity. The SERS performance and photocatalytic activity of Ag/TiO2 nanostructures are demonstrated by the test analyte Rhodamine 6G detection down to concentrations of 10-12 M and acceleration of its degradation under simulated sunlight by 5.8 times. Tests with tetracycline water solutions indicate a nanomolar detection limit and 4.4-fold increase in degradation rate. The proposed Ag/TiO2 nanostructures are prospective for creation of low-cost bifunctional platforms for the sensitive detection of organic residues in water as well as their fast neutralization under solar light.

Enhanced photocatalytic activity in AgCu-decorated ZnO nanoparticles under UV and sunlight

This study investigates the structural, morphological, and photocatalytic properties of monometallic (Ag and Cu) and bimetallic (AgCu) nanoparticles (NPs) incorporated into ZnO NPs and their photocatalytic performance. X-ray diffraction and Rietveld refinement were employed to analyze the structural characteristics, revealing the formation of a hexagonal wurtzite structure of ZnO and cubic phases of Ag and Cu within the metal-decorated NPs. Scanning electron microscopy provided visual evidence of the spherical morphology, with an average particle size of 50 nm. Energy-dispersive X-ray spectroscopy confirmed the successful deposition of Ag, Cu, and AgCu NPs onto the ZnO surface. The photocatalytic efficiency of the NPs was evaluated by the degradation of methylene blue dye under UV light at a wavelength of 254 nm under sunlight irradiation. Under UV light, the bimetallic AgCu/ZnO system exhibited exceptional performance, achieving a degradation rate of about 95% with 10% AgCu/ZnO. Conversely, under sunlight illumination, the monometallic Cu/ZnO and Ag/ZnO NPs exhibited outstanding photocatalytic properties, with degradation rates of about 99 and 98%, respectively. These findings underscore the influence of the light source on photocatalytic performance as well as the significance of the plasmonic effects and charge-transfer mechanisms.

Constructed of Cd-based organic framework heterostructure material for solar-powered organic dye purification

A novel water-stable Cd-based organic framework material (Cd-MOF) has been synthesized based on the 4,4′-([2,2′-bipyridine]-6,6′-diylbis(oxy))phthalic acid (H4L) ligand and Cadmium nitrate tetrahydrate (Cd(NO3)2·4H2O) with a solvothermal method. We also prove that the rational design and preparation of Cd-MOF\\Ag heterojunctions by depositing Ag nanoparticles on the surface of Cd-MOF is an effective photocatalyst for the degradation of organic dyes in water. The photodegradation rates of RhB and MO were significantly improved under simulated sunlight conditions (AM1.5G), which reaching 0.68 and 1.549 min−1 g−1, respectively. The prominent performance is attributed to the efficient separation of photo-generated electrons and holes caused by the composite heterojunction of Cd-MOF/Ag. The surface plasmonic resonance (SPR) effect of Ag nanoparticles and the Schottky junction between Ag and Cd-MOF play crucial role in the photocatalytic degradation process. This work provides a new strategy for preparing photocatalysts and promoting the development of the degradation of organic dye pollutants in effluent with MOF-based material as photocatalysts.

Ultrasound-Driven Deposition of Au and Ag Nanoparticles on Citrus Pectin: Preparation and Characterisation of Antimicrobial Composites.

Pectin is a renewable, non-toxic and biodegradable polymer made of galacturonic acid units. Its polar groups make it suitable for complexing and supporting metallic nanoparticles (NPs). This work aimed to produce antibacterial nanocomposites using pectin and acoustic cavitation. The metal NPs (Au or Ag) were deposited using ultrasound (US, 21 kHz, 50 W) and compared with those achieved with mechanical stirring. The impact of the reducing agents (NaBH4, ascorbic acid) on the dispersion and morphology of the resulting NPs was also assessed. Characterization by diffuse reflectance (DR) UV-Vis-NIR spectroscopy and field emission scanning electron microscopy (FESEM) showed that the use of US improves the dispersion and decreases the size of both Au and Ag NPs. Moreover, with Au NPs, avoiding external reductants led to smaller NPs and more uniform in size. The prepared NPs were functionalized with oxytetracycline in water and tested against Escherichia coli (gram negative) and Staphylococcus epidermidis (gram positive) via the Kirby-Bauer test. The results show a better antibacterial activity of the functionalized nanoparticles compared to antibiotic-free NPs and pure oxytetracycline, advising the potential of the nanoparticles as drug carriers. These findings underscore the significance of US-assisted synthesis, paving the way to new environmentally friendly antimicrobial materials.

Anisotropic Magnetic Polymeric Particles with a Controllable Structure via Seeded Emulsion Polymerization.

Magnetic polymer composites have been widely utilized in potential applications in material science, such as reduction of dyes, immunodiagnostics, biomedicals, and magnetically controllable photonic crystals owing to large surface areas, fast separation, and recyclable performance. In this work, anisotropic magnetic particles were prepared by seeded emulsion polymerization, with morphologies of "Fe3O4-shell", "hemisphere-like", "raspberry-like", "multiple lobes-like", and "sandwich-like". Poly(styrene/divinylbenzene/mono-2-(methacryloxy)ethyl succinate)@ Fe3O4 (P(St/DVB/MMES)@Fe3O4) were the seed microspheres, and P(St/DVB/MMES)@Fe3O4@polymer particles are achieved by seeded emulsion polymerizations. The morphology of the particles depends on polymerization conditions (monomer ratios and surfactant), particle properties, and so on. Then, the minimum surface free energy change principles were used to predict the equilibrium morphologies of the magnetic polymer composites. Through theory, the model gives the correct tendency and good agreement with the equilibrium morphology which was in tandem with TEM results. Lastly, after in situ surface deposition of Ag nanoparticles, magnetic composite particles with sandwich-like morphology were applied for the catalytic degradation of 4-nitrophenol (4-NP) reacting with NaBH4. The apparent rate coefficient is 0.0069 s-1, and it can keep mainly about 80% efficiency in catalysis after five cycles.

A Sandwich Structure Ag/MgFe2O4-Deposited Surface Carbonized Wood for Integrated Solar Steam Generation and Photoreduction of Cr(VI).

The severe deterioration of the marine ecosystem significantly negatively impacts the performance of solar-driven steam generation (SSG) and the quality of the obtained freshwater. Herein, a bifunctional Ag/MgFe2O4@SCW reactor with a sandwich structure is designed for efficient SSG and Cr(VI) reduction, which is constructed via in situ deposit Ag nanoparticles (NPs) and MgFe2O4 onto surface carbonized wood (SCW). Owing to the advanced sandwich structure and strong interfacial interactions between each component, an ultra-high evaporation rate of 1.55kg m-2 h-1 and the efficiency of 88.6% are achieved using Ag/MgFe2O4@SCW under 1 sun. The system exhibits the long-term evaporation performance in the simulated sewage and strong acid/base solutions along with water-harvesting capacity in outdoor solar desalination. The quality of distilled water after desalination of actual seawater and NaCl solutions with different concentrations meets the WHO-recommended drinkable water standards. Furthermore, Ag/MgFe2O4@SCW shows outstanding antibacterial property, self-desalting capacity, as well as reusability and structure stability. Most importantly, the fast carrier separation endows Ag/MgFe2O4@SCW with superior photocatalytic activity and Cr(VI) photoreduction of up to 96.1% after 180min of illumination. The bifunctional Ag/MgFe2O4@SCW reactor provides an advanced synergistic mechanism for improving SSG and photocatalytic performance, while being promising for solar-powered production of clean water.

Enhanced performances of NiCoSe2 electrode coated with Ag nanoparticles by magnetron sputtering for the applications of asymmetric supercapacitors

In this work, a binder-free energy-storage electrode material of Ag nanoparticles coated nickel cobalt selenide (NiCoSe2) on Ni foam (NF) was first proposed. Wherein, NiCoSe2 was synthesized by one-step hydrothermal method using ascorbic acid as reductant, and the coating of Ag nanoparticles on NiCoSe2 were performed by magnetron sputtering method. The specific surface area was greatly increased due to the deposited Ag nanoparticles, and in this way the impedance of the electrode decreased, and the electrochemical properties were enhanced. When the magnetron sputtering time is 10 s, Ag/NiCoSe2 electrode exhibits the most excellent performances. However, further increase of sputtering time may result in the over cover on NiCoSe2, with great deterioration in electrochemical behavior. Single NiCoSe2 electrode possesses an area capacitance of 1600.7 mF cm−2 at a current density of 2 mA cm−2, while Ag/NiCoSe2 electrode could reach up to 2280 mF cm−2. The asymmetric supercapacitor (ASC) assembled by Ag/NiCoSe2 and activated carbon (AC) electrodes shows a high energy density of 0.171 mWh cm−2 as well as a power density of 17.340 mW cm−2, and the cyclic stability remains at 90.1% after 4000 cycles, which is superior to 83.7% of the NiCoSe2 single electrode.

The effect of a polymer capping agent on electrodeposited silver nanoparticles in a silver deposition-based electrochromic device.

In this study, polyvinylpyrrolidone (PVP) was introduced into an Ag deposition-based electrochromic (EC) device as a capping agent for electrodeposited Ag nanoparticles (AgNPs) to improve the coloration characteristics of EC devices and to precisely control the size and shape of the AgNPs. Through the coordination of PVP molecules with Ag+ ions in the EC electrolyte, the critical voltage for the deposition of AgNPs decreased, resulting in a lower operating voltage of the EC device in comparison with the conventional one. Because particle growth and AgNP aggregation were suppressed by the capping effect of PVP, uniform electrodeposition of AgNPs was achieved. Aggregation suppression enabled vivid cyan, yellow, and red coloration using a simple driving procedure. The suppression of AgNP aggregation by PVP was demonstrated even in an electrochemical system. Furthermore, the capping effect of PVP also improved image retention. Better color retention properties were achieved even without the use of any counter-modified electrode cells.

Photodeposition synthesis of hollow g-C3N4/Ag nanotubes with high oxidation properties to enhance visible-light photocatalytic performance

A hollow Ag-deposited g-C3N4 nanotube (CNNT/Ag) with high oxidation properties was synthesized using a simple photodeposition method. The g-C3N4 nanotubes provided abundant active sites and a large specific surface area for effective deposition of Ag nanoparticles. The Ag NPs expanded the light absorption range of g-C3N4 through surface plasmon resonance (SPR) effects and acted as an electron acceptor, effectively inhibiting the recombination of photogenerated carriers, thereby improving the charge separation efficiency. The CNNT/Ag composites exhibited excellent photocatalytic performance in the visible light degradation of rhodamine B and tetracycline, 6.42 and 2.16 times higher than pure g-C3N4, respectively. The increased photocatalytic activity of CNNT/Ag composites was attributed to the synergistic electron transfer interface between CNNT and Ag NPs, promoting the migration efficiency of photo-generated carriers. This work presented a promising strategy for constructing effective photocatalysts for degrading organic pollutants using morphology optimization and SPR effects on noble metal surfaces.

Ag nanoparticles decorated ZnO nanopagodas for Photoelectrochemical application

Photoelectrochemical water splitting (PEC-WS) utilizing solar energy and photoelectrodes immersed in an electrolyte has sparked an increased interest in hydrogen production. The PEC-WS efficiency is enhanced by controlling the nanostructure of photoelectrodes and sensitizing them with plasmonic metals. This study shows how the transformation from ZnO nanorods to ZnO nanopagodas and the deposition of Ag nanoparticles improve the photocurrent and PEC conversion efficiency under sunlight. The deposition of an optimal amount of Ag nanoparticles over ZnO nanopagodas exhibited the highest photocurrent of 2.15 mA cm−2 at 1.23 V vs RHE, while pure ZnO nanorods and nanopagodas achieved 0.90 and 1.43 mA cm−2, respectively. This extraordinary improvement in photocurrent density was thoroughly analyzed using various PEC and optical measurements as well as electromagnetic simulation. As a result, two main reasons for the improvement were derived. Firstly, ZnO nanopagodas can reduce the charge recombination rate due to the reduced structural defects and improve the light-harvesting ability due to their distinct superstructure characteristics. Secondly, the deposition of plasmonic Ag nanoparticles can improve the interfacial charge transfer and increase the ability to capture visible light due to their localized surface plasmon resonance effects.

Accumulation of Ag(0) Single Atoms at Water/Mineral Interfaces during Sunlight-Induced Reduction of Ionic Ag by Phenolic DOM.

Silver (Ag) undergoes a complex and dynamic Ag+/Ag0 cycle under environmental conditions. The Ag+ → Ag nanoparticles (AgNPs) transformation due to the combined actions of sunlight, O2, and dissolved organic matter has been a well-known environmental phenomenon. In this study, we indicate that this process may be accompanied by a pronounced accumulation of Ag(0) single atoms (Ag-SAs) on the minerals' surfaces. According to spherical aberration-corrected scanning transmission electron microscopy and high-energy-resolution X-ray adsorption fine structure analyses, humic acid (HA) and phenol (PhOH) can induce Ag-SAs accumulation, whereas oxalic acid causes only AgNPs deposition. Ag-SAs account for more than 20 wt % of total Ag(0) on the γ-Al2O3 surfaces during HA- and PhOH-mediated photolysis processes. HA also causes Ag-SAs to accumulate on two other prevalent soil minerals, SiO2 and Fe2O3, and the fractions of Ag-SAs are about 15 wt %. Our mechanism studies suggest that a phenolic molecule acts as a reducing agent of Ag+ and a stabilizer of Ag-SAs, protecting Ag-SAs against autocatalytic nucleation.

Ultraviolet Exposure Improves SERS Activity of Graphene-Coated Ag/ZrO2 Substrates

This study reveals a significant improvement in surface-enhanced Raman scattering (SERS) activity of Ag/ZrO2 substrates covered with a few-layer graphene preliminary exposed to ultraviolet (UV) light. The SERS-active substrates are formed by the “silver mirror” deposition of Ag nanoparticles on annealed zirconia blocks. The film composed of ~3 graphene layers is grown on copper foil by a chemical vapor deposition and then wet-transferred to the SERS-active substrates. The graphene-free Ag/ZrO2 samples are found to provide an enhancement of the Raman scattering from rhodamine 6G (R6G) at a micromolar concentration, which is associated with combined effects from the surface plasmon resonance in the Ag nanoparticles and a charge transfer facilitated by zirconium dioxide. It is revealed that the SERS signal from the analyte molecules can be suppressed by a UV exposure of the Ag/ZrO2 samples due to photocatalytic activity of the wide band gap semiconductor. However, if the samples are covered with a few-layer graphene (Gr/Ag/ZrO2) it prevents the dye molecule decomposition upon the UV treatment and improves SERS activity of the substrates. The 365 nm treatment leads to a 40% increase in the 10–6 M R6G SERS spectrum intensity, while the 254 nm irradiation causes it to rise by 47%, which is explained by different responses from the surface and bulk zirconia crystals to the short and long UV wavelengths. This enhancement is attributed to the distinct responses of surface and in-depth zirconia crystals to varied UV wavelengths and underscores the pivotal role of graphene as a protective and enhancing layer.

Anodizing of commercial galvanized mesh followed by electroless decorating of Ag nanoparticles for application as novel and low-cost photocatalyst for degradation of both dye and microbiological pollutants

In the current work, novel and low-cost photocatalyst-mesh for effective degradation of both dye and microbiological pollutants is introduced. The Ag nanoparticles/anodized galvanized meshes (AgNPs/AGMs) were easily fabricated through electrochemical anodization of commercially galvanized meshes, calcination in the optimized temperature and finally deposition of Ag nanoparticles via electroless treatment. Effective parameters on photocatalytic behaviors of photocatalyst-meshes containing anodizing voltage, anodizing time, calcination temperature and electroless time of AgNPs were carefully optimized. Surface morphology and photocatalytic characterization of meshes were studied by FESEM, ATR-IR, XRD, EDX, UV–Vis DRS and EIS analyses. Antibacterial activities of meshes for degradation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria were investigated in Brain Heart Infusion (BHI) and Mueller-Hinton Broth (MHB) at 37 °C for 18 h. The AgNPs/AGMs revealed significant photocatalytic activity as well as recyclability for degradation of methylene blue dye under UV-light irradiation within 30 min (79.52 %). Moreover, the AgNPs/AGMs exhibited excellent E. coli and S. aureus inactivation efficiency compared to AGMs and bare galvanized meshes. It is expected that AgNPs/AGMs can be used as suitable photocatalysts for degradation of both chemical and biological pollutants in industrial scale.

In-situ deposition of silver nanoparticles on cuprous oxide hollow spheres for sensitive and recyclable SERS sensing in solution based on electromagnetic and chemical enhancement

In order to achieve widespread application of surface-enhanced Raman spectroscopy (SERS) technique for practical sensing illegal additives in food, it is crucial to construct a reliable SERS substrate that offers both high sensitivity and reusability. This work utilized a simple and rapid in-situ deposition method to deposit Ag nanoparticles onto hollow Cu2O nanospheres, resulting in the formation of Cu2O/Ag nanocomposites with photocatalytic and SERS properties. These nanocomposites were employed as a hopeful SERS analysis for effective sensing of colorant additives in fruit juice, including methylene blue (MB) and rhodamine 6G (R6G). Impressively, the nanocomposites exhibited an exceptional detection limit of 10−9 M for the color agents and demonstrated a strong linear relationship between SERS intensities and the logarithmic concentration (R2 ≥ 0.95). The hollow structure of Cu2O provided low density and long-term dispersion stability in solution, which are beneficial for real-time monitoring the additives in liquid food. The excellent SERS performance can be attributed to the electromagnetic effect of Ag metals and the chemical enhancement of Cu2O semiconductors, as confirmed by the N 1 s XPS spectra from MB. Furthermore, the Cu2O/Ag nanocomposites efficiently degraded dye molecules under UV light irradiation within a short period of 45 min. So, the nanocomposites exhibited practical recyclability, as demonstrated by their consistent performance over five cycles of SERS sensing. These findings highlight their significant potent for SERS sensing trace pollutants and ecological restoration by photocatalytic reaction in the future.

Synthesis of recyclable SERS platform based on magnetic Fe3O4/mTiO2/Ag composites for photodegradation and identification of organic pollutants in different water samples

In this study, we coatedmagnetic Fe3O4 nanospheres with a crystalline mesoporous TiO2 (mTiO2) layer with photocatalytic activity, followed by the deposition of Ag nanoparticles as an outer layer through in-situ reduction of AgNO3 to obtain multifunctional Fe3O4/mTiO2/Ag core-shell-shell structured composites. By adjusting the amount of AgNO3, we were able to precisely control the size and coverage of the Ag nanoparticles. To evaluate the surface-enhanced Raman spectroscopy (SERS) activity of the Fe3O4/mTiO2/Ag composites, we employed 4-mercaptobenzoic acid (4-MBA) as a model Raman reporter. The limit of detection (LOD) of 4-MBA was down to 10−10 M. Moreover, for practical applications, we successfully detected methylene blue (MB) in different water samples, such as tap water and industrial wastewater, and both of systems presented an ultralow LOD of 10−9 M. Notably, a strong linear relationship (R2 ≥ 0.95) between the SERS intensities and the logarithmic concentration of MB was observed, highlighting the excellent quantitative sensing capabilities of these substrates. The Fe3O4/mTiO2/Ag composites also exhibited remarkable signal reproducibility and exceptional stability during storage. Additionally, these composites demonstrated promising photocatalytic property. In five consecutive cycles, we were able to efficiently detect MB by utilizing the composites' photocatalytic removal ability under UV irradiation, which was facilitated by simple magnetic separation. These findings hold significant importance for environmental safety and pollutant removal applications.

Synthesis of a capillary surface-enhanced Raman scattering substrate integrating sampling and detection based on meniscus self-assembled technology.

A method is proposed to fabricate a novel capillary surface-enhanced Raman scattering (SERS) substrate integrating sampling and detection based on meniscus evaporation self-assembled technology, named Meniscus@AgNPs@Capillary substrate. Ag nanoparticles (AgNPs) were arranged in the inner wall of the capillary through meniscus evaporation. The parameters which might affect the deposition of AgNPs during evaporation were investigated, including the evaporation temperature, self-assembly time, the ratio of silver sol to ethanol, and capillary length. The enhancement effect of SERS under different fabrication conditions was investigated using rhodamine 6G (R6G) as a Raman probe. Moreover, the optimal fabricated Meniscus@AgNPs@Capillary substrate was applied to the detection of several environmental pollutants such as polystyrene nanoplastics (PSNPs) and various antibiotics, with limits of detection (LOD) of 10 µg/L and 1 µg/L, respectively. The Meniscus@AgNPs@Capillary substrate presented the advantages of time and effort saving, high sensitivity, and on-site sampling and testing.

Preparation of thiol-decorated Ag nanoparticles on N-doped carbon through resonant acoustic mixing for electrochemical CO2 reduction

The development of electrocatalysts with high selectivity and low overpotentials has been a prominent area of focus in electrochemical CO2 reduction (ECR) research. Supported metal nanoparticle (NP) has been received considerable interest due to the immense potential of remarkable activity, stability, and recyclability in ECR applications. However, the practical production of these supported metal NPs necessitates a facile and scalable approach. Addressing this challenge, the present study introduces a novel method for solid-state synthesis of Ag/C using resonant acoustic mixing (RAM). The RAM technique successfully facilitated the deposition of Ag nanoparticles onto n-doped carbon support, forming Ag/N-C catalysts. The as-prepared Ag electrocatalysts exhibited excellent dispersion and uniformity in terms of particle size. A thiol-decorated Ag electrocatalyst (Ag-Th/N-C) was prepared using a simple soaking method to establish an Ag-thiol interface enhancing catalytic activity caused by promoted electron transfer from Ag to CO2. Significantly, the Ag-Th/N-C catalyst demonstrated an improved Faradaic efficiency of 87.26% for the reduction of CO2 to CO at − 1.1 V versus RHE compared to the pristine Ag/C catalyst (55.45%).

Fabrication of Z-scheme ZnO/g-C3N4 heterojunction modified by silver nanoparticles for photocatalytic removal of Norfloxacin and Rhodamine B

A novel ternary photocatalyst with a Z-scheme heterojunction was successfully synthesized through the deposition of Ag nanoparticles onto the surface of a ZnO/g-C3N4 composite. The prepared photocatalysts were characterized by XRD, FT-IR, XPS, HRSEM, TEM, DRS, PL, EIS, TPC, and M-S. The photocatalytic performance of the as-synthesized photocatalysts was systematically investigated through the photodegradation of norfloxacin (NOR) and rhodamine B (RhB) under visible light irradiation. The photodegradation efficiency of 5% Ag/ZnO/g-C3N4 (5AZCN) composite photocatalyst reached 86.7% (480 min) and 98.0% (60 min) for NOR and RhB, respectively. Moreover, the apparent rate constants of the 5AZCN composite photocatalysts for NOR and RhB were found to be 3.4 and 22.2 times higher than that of the ZCN composite photocatalysts, respectively. The significantly enhanced photocatalytic performance was ascribed to the widened range of visible light response and the efficient separation and migration of carriers facilitated by the introduction of Ag nanoparticles that functioned as electron transfer mediators. Based on the free radicals quenching experiment and electron spin resonance (ESR) spectroscopy characterization, superoxide radicals (·O2−) were the main reactive species in the photodegradation process. Furthermore, the charge transfer process was proved to be a Z-scheme transfer mechanism. This work provides a promising approach to simply constructing novel efficient Z-scheme photocatalysts for the elimination of environmental pollutants.

Investigation of Antibacterial Activity of Ag-CuO and Ag-ZnO Nanocomposites synthesized by Chemical Precipitation Method

In this present study, the synthesis of Ag-CuO and Ag-ZnO nanocomposites has been conducted. The individual Ag-CuO and Ag-ZnO nanocomposites were synthesized by using chemical precipitation method. The resulting particles were characterized by using UV-Visible, FTIR, XRD and SEM. The optical properties and band gap measurements were explored by UV-Visible spectroscopy. FTIR spectrum of the prepared nanocomposite revealed the presence of vibrational modes which were related to the Cu-O, Zn-O. The XRD analysis confirmed the structural purity of synthesized nanocomposites and the estimated crystallite size is 31.93 nm and 26.62 nm for Ag-CuO and Ag-ZnO nanocomposites respectively. The morphological features were explored by SEM analysis with deposition of Ag nanoparticles on the surface of metal oxide nanoparticles. The antibacterial activities of synthesized nanocomposites were tested on bacteria strains such as Escherichia coli (Gram -ve) and Staphylococcus aureus (Gram +ve) respectively through well diffusion method. The synthesized nanocomposite shows the higher efficacy against E.coli with an average diameter size of 17 mm zone of inhibition. This result suggests that Ag-CuO and Ag-ZnO nanocomposites can be used effectively against microbial growth. Therefore, the synthesized nanocomposite may be promising for the antibacterial agent in pharmaceutical applications.