Distribution Of Ag Nanoparticles Research Articles

The Optimization of the Synthesis of Antibacterial Coatings on Ti6Al4V Coupons Obtained by Electron Beam Melting

Prosthetic joint infection represents a problem that worsens the patient’s quality of life and produces an economic impact on health systems. We report the anodization of Ti6Al4V coupons obtained by electron beam melting to produce a nanostructured surface. Anodization at 10 V produced TiO2 nanopores with a diameter in the range of 15–20 nm. Thereafter, Ag nanoparticles (AgNPs) were deposited in three different ways to provide antibacterial functionality to the coatings: electrochemically, thermally, and chemically. The electrochemical method did not provide good coverage of AgNPs. At 0.1 V of synthesis potential, cubic, octahedral, and truncated octahedral Ag crystals were obtained. The thermal method provided a good distribution of AgNPs but it damaged the TiO2 nanostructure. The chemical method showed the best distribution of AgNPs over the anodized surface and preserved the anodized nanostructure. For this reason, the chemical method was selected to perform further studies. Ag+ release was monitored in simulated body fluid at 37 °C, reaching 1.86 mg Ag+/L after 42 days. The antibacterial coating showed excellent antibacterial activity and inhibited biofilm formation for Staphylococcus epidermidis RP62A and Staphylococcus aureus V329 strains (lethality > 99.9% for both bacteria and assays).

Green synthesis of Carica papaya mediated silver nanoparticles: Characterization, antibacterial activity, and bioelectricity generation for sustainable applications in nanotechnology

This study presents a sustainable method for synthesizing silver nanoparticles (Ag NPs) using green Carica papaya extract (CPE) as a reducing and stabilizing agent. The green synthesis minimizes environmental impact and utilizes bioactive compounds in Carica papaya (CP), offering an economical and sustainable alternative. The goal is to employ CPE for the eco-friendly synthesis of Ag NPs, followed by comprehensive characterization, antibacterial evaluation, cytotoxicity against brine shrimp, and examination of bioelectricity generation. Locally sourced CP was boiled in deionized water, then cooled and filtered twice. The bio-reduction of silver ions to Ag NPs was confirmed by a color change when 45 mL of 0.005 M AgNO3 was mixed with 5 mL of CPE. Characterization through UV–vis absorption spectrophotometry (UV), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy (EDX), Transmission electron microscopy (TEM), and Gas chromatography-mass spectrometry (GC–MS) analysis confirms the successful formation and consistent size distribution of Ag nanoparticles. CPE is a crucial reducing agent, as evidenced by a distinct UV-visible peak at 422 nm. X-ray crystal analysis verifies highly crystalline Ag NPs with a face-centered cubic lattice structure. The d-spacing values in SAED images are consistent with the results obtained from XRD. Antimicrobial effectiveness against Escherichia coli and Staphylococcus epidermidis is demonstrated. The study explores the bioelectricity generation potential of CPE-synthesized Ag NPs, indicating promising prospects for sustainable energy solutions. Preliminary experiments show the ability of the nanoparticles to catalyze bio-electrochemical reactions. This dual-benefit study underscores CPEs role in antibacterial properties and bioelectricity generation, laying the groundwork for further research in sustainable nanotechnology applicable to healthcare and energy sectors and contributing to the advancement of environmentally friendly technologies.

Synthesis and photocatalytic mechanism study of visible light-driven Z-type Ag/AgBr/Bi2MoO6 composite materials for efficient degradation of organic dyes

The synthesis of the Ag/AgBr/Bi2MoO6 nanocomposite was achieved through a facile hydrothermal method combined with in situ photodeposition. Subsequently, its efficacy in catalyzing the degradation of Rhodamine B (RhB) under visible light irradiation was systematically investigated. The Bi2MoO6 samples and the Ag/AgBr/Bi2MoO6 nanocomposites underwent comprehensive characterization using a suite of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The analyses unveiled a homogeneous distribution of Ag nanoparticles on the surface of AgBr/Bi2MoO6, indicative of the successful formation of the composite. To assess the photocatalytic efficiency, the degradation of RhB under visible light irradiation was employed as a benchmark. Notably, the incorporation of Ag nanosheets, serving as electron mediators and Schottky barriers, facilitated efficient electron transfer between Bi2MoO6 and AgBr. Consequently, the photocatalytic activity of the ternary Z-type heterogeneous Ag/AgBr/Bi2MoO6 nanocomposites surpassed that of the pure Bi2MoO6 and AgBr samples. Remarkably, under 12 min of visible light irradiation, the photocatalytic activity of the Ag/AgBr/Bi2MoO6 nanocomposites reached an impressive 99.99 %.

Stable ultrathin lithium metal anode enabled by self-adapting electrochemical regulating strategy

Ultrathin lithium (Li) metal foils with controllable capacity could realize high-specific-energy batteries; however, the pulverization of Li metal foils due to its extreme volume change results in rapid active Li loss and capacity fading. Here, we report a strategy to stabilize ultrathin Li metal anode via in-situ transferring Li from ultrathin Li foil into a well-designed three-dimensional gradient host during a cycling process. A three-dimensional carbon fiber with gradient distribution of Ag nanoparticles is placed on the ultrathin Li foil in advance and acts as a Li reservoir, guiding Li deposition into its interior and thus alleviating the volume change of ultrathin Li foil anodes. Hence, a high reversibility of Li metal is achieved and Li pulverization is suppressed, which can be witnessed by a long cyclic life in the symmetric cells. The proposed method offers a versatile and facile approach for protecting ultrathin Li metal anodes, which will boost their commercial application process.

Raman characteristics of graphene/quartz and graphene/Ag nanoparticles/quartz substrate: Laser power dependence

The sensitivity of graphene surface to adjacent conditions plays an important role that modifies the performance and characteristics of graphene devices working under ambient conditions. Quartz is a dielectric transparent material with excellent optical transmission and therefore graphene/quartz is widely used in graphene device technology. Here, graphene/quartz and graphene/plasmonic nanoparticle/quartz structures were investigated using Raman spectroscopy for applications in nanotechnology like graphene quartz fiber (GQF) multifunctional electrode. Optically induced shift of the Fermi level of graphene monolayer on quartz substrates and on Ag nanoparticles (NPs) distributed on quartz substrates was tracked by increasing the applied laser power. Strained graphene attached to quartz substrate, thermal effects, and charge transfer were discussed using the evolution of the G-peak characteristics. Well distributed Ag NPs on quartz substrate are shown by scanning electron microscopy; an interesting property of plasmonic nanoparticles on quartz substrates. The graphene on single Ag NP verified using Raman mapping images by the surface enhanced Raman G-peak on the Ag NP. The Ag NP was driven to the plasmonic resonance by selecting the laser probe wavelength and the localized surface plasmons excited in Ag NPs were inferred by the transmission and photoluminescence spectra. Investigations of graphene on quartz and on plasmonic nanoparticles/quartz substrates can help for GQF hybrid structures which combines the enhanced thermal and electrical conductivity of graphene/plasmonic nanoparticles in addition to the extraordinary properties of quartz fibers suitable for sensing applications.

Turi leaf extract Ag nanoparticle liquid soap (Review of physical properties and antibacterial activity)

Research has been carried out on manufacturing liquid soap silver nanoparticles of Turi leaf extract. Ag nanoparticles have been used in various cosmetic and personal care products. This is because Ag nanoparticles have potential advantages such as increasing product stability, increasing absorption, and the ability to give special effects to the skin. From the physical properties test results, all soap formulas meet the standards set based on organoleptic, physical properties, pH, density, and viscosity. This research discusses the antibacterial activity of liquid soap. Formula 1 showed better antibacterial activity than formulas 2 and 3, with an inhibitory area reaching 23.84 mm. This can be explained by the fact that Formula 1 has a smaller particle size, namely 2161 nm. Formula 1 has the lowest AgNO3 concentration. The higher the concentration of AgNO3 used in the synthesis, the greater the amount of Ag+ that must be reduced, resulting in greater agglomeration and a larger size distribution of Ag nanoparticles.

Long-Range Uniform Deposition of Ag Nanoseed on Cu Current Collector for High-Performance Lithium Metal Batteries.

Uniform lithium deposition is essential to hinder dendritic growth. Achieving this demands even seed material distribution across the electrode, posing challenges in correlating the electrode's surface structure with the uniformity of seed material distribution. In this study, the effect of periodic surface and facet orientation on seed distribution is investigated using a model system consisting of a wrinkled copper (Cu)/graphene structure with a [100] facet orientation. A new methodology is developed for uniformly distributed silver (Ag) nanoparticles over a large area by controlling the surface features of Cu substrates. The regularly arranged Ag nanoparticles, with a diameter of 26.4nm, are fabricated by controlling the Cu surface condition as [100]-oriented wrinkled Cu. The wrinkled Cu guides a deposition site for spherical Ag nanoparticles, the [100] facet determines the Ag morphology, and the presence of graphene leads to spacings of Ag seeds. This patterned surface and high lithiophilicity, with homogeneously distributed Ag nanoparticles, lead to uniform Li+ flux and reduced nucleation energy barrier, resulting in excellent battery performance. The electrochemical measurements exhibit improved cyclic stability over 260 cycles at 0.5mAcm-2 and 100 cycles at 1.0mAcm-2 and enhanced kinetics even under a high current density of 5.0mAcm-2.

Urchin-like covalent organic frameworks templated Au@Ag composites for SERS detection of emerging contaminants.

Au@Ag core-shell composites were successfully fabricated on urchin-like covalent organic frameworks (COFs), providing a platform with numerous hot spots for the detection of two categories of emerging contaminants: sulfonamide antibiotics and nanoplastics, using surface-enhanced Raman spectroscopy (SERS). Au seeds (∼10 nm) were generated on the COFs, leveraging the reducing properties of the vinyl and imino groups within the framework. This ensured the growth of dense and uniformly distributed Ag nanoparticles. The COFs exceptionally large surface area (2324 m2 g-1) and high adsorption capacity, significantly contributed to the enrichment and detection of trace pollutants. As a result, using a portable Raman spectrometer, limits of detection of 0.008 μmol L-1 for sulfamethoxazole and 0.029 mg L-1 for polystyrene nanoplastics were achieved.

An efficient wastewater treatment through reduction of organic dyes using Ag nanoparticles supported on cellulose gum beads

This work reports silver nanoparticles (AgNPs) supported on biopolymer carboxymethyl cellulose beads (Ag-CMC) serves as an efficient catalyst in the reduction process of p-nitrophenol (p-NP) and methyl orange (MO). For Ag-CMC synthesis, first CMC beads were prepared by crosslinking the CMC solution in aluminium nitrate solution and then the CMC beads were introduced into AgNO3 solution to adsorb Ag ions. Field emission scanning electron microscopy (FE-SEM) analysis suggests the uniform distribution of Ag nanoparticles on the CMC beads. The X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis revealed the metallic and fcc planes of AgNPs, respectively, in the Ag-CMC catalyst. The Ag-CMC catalyst exhibits remarkable reduction activity for the p-NP and MO dyes with the highest rate constant (kapp) of a chemical reaction is 0.519 and 0.697 min−1, respectively. Comparative reduction studies of Ag-CMC with CMC, Fe-CMC and Co-CMC disclosed that Ag-CMC containing AgNPs is an important factore in reducing the organic pollutants like p-NP and MO dyes. During the recyclability tests, the Ag-CMC also maintained high reduction activity, which suggests that CMC protects the AgNPs from leaching during dye reduction reactions.

Evaluation of chitosan-Ag/TiO2 nanocomposite for the enhancement of shelf life of chili and banana fruits

Post-harvest losses of fruits and vegetables account for a large share of food waste in the world due to improper handling and packaging. By using the sol-gel method, Ag/TiO2 nanocomposite was prepared in this study from micro-sized commercial TiO2 powder and incorporated in a chitosan-cellulose matrix for the purpose of promising food packaging. The particle size and distribution of Ag nanoparticles (9.2437 nm size) confirmed their successful inclusion in the TiO2 surface. The morphology of the package assured the successful and uniform disbursement of Ag/TiO2 nanocomposite into the chitosan-cellulose matrix, which led to enhanced water resistance and photocatalytic activity. The developed package is proficient in hindering the growth of fecal coliform bacteria (Esche (Escherichia coli) by 9 mm in the agar plate. Moreover, the efficient application of chitosan-Ag/TiO2 nanocomposite in food coating and packaging was examined in extending shelf life, minimizing water loss, and preventing microbial infection during the storage of chili (up to 7 days at 37 °C) and banana, respectively. It can be concluded from the results that chitosan-Ag/TiO2 nanocomposite-based food coating and packaging have competent potential for enhancing the shelf life of moist foods.

Facile one−step synthesis of Ag anchoring on Cu2O for enhanced SERS activity: Efficient charge transfer and adsorption

There is a keen research interest to develop inexpensive and ultrasensitive substrate materials for practical sensing application of surface enhanced Raman spectroscopy (SERS). Aiming to utilize synergistic enhancement contributions originated from plasmon adsorption and charge transfer (CT), it is highly desirable to construct hybrid substrates of noble metals and semiconductors. In this work, Ag nanoparticles−decorated Cu2O hybrids (Ag−Cu2O) were synthesized through a simple one−step growth method, i.e., reducing AgNO3 and CuCl2 by ascorbic acid (AA) in the presence of PVP. A systematic study has been carried out to characterize the material properties and SERS performance of Ag−Cu2O hybrids prepared under different molar ratios of precursors, growth temperatures and addition speed of reducing agent. Ag−Cu2O hybrids, composed of well−distributed Ag nanoparticles on Cu2O nanoplates, showed enhanced SERS performance in comparison with pure Cu2O. When 4−nitrobenzenethiol (4−NBT) was used as probe molecule, the optimal sample showed a calculated enhancement factor of 1.4 × 105 and a low detection of limit (LOD) of 1 × 10−10 M, which is four orders of magnitude lower than that of pure Cu2O. Ag−Cu2O hybrid substrates can also be used to detect dye molecues and the LODs for rhodamine 6G and crystal violet were 1 × 10−8 M and 1 × 10−9 M, respectively. It is feasible that the observed enhancement of SERS activity were benefited from synergistic contributions of the abundant “hot spots”, rich photo−induced charge transfer pathways, improved adsorption ability, and suppressed recombination of e−h pairs in Ag−Cu2O hybrids. This work provides a simple and controllable approach to fabricate metal/semiconductor hybrids as SERS sensing platform.

Photoluminescence enhancement of Nd3+ doped antimony borate glasses by inclusion of silver nanoparticles

Effect of silver (Ag) nanoparticles (NPs) on photoluminescence (PL) attributes of trivalent neodymium ions bearing glass specimens has been examined and described the outcomes in detail. The presence and distribution of Ag NPs were confirmed using transmission electron microscopic measurement. The luminescence enhancement factor (LEF) for the 1055 nm PL emission peak was boosted from 1.33 to 2.53 when the AgNO3 content elevated from 0.2 to 0.6 mol % and subsequently for 0.8 mol% of AgNO3 the LEF was decreased to 2.38. The stimulated emission cross–section, quantum efficiency, and emission bandwidth magnitudes of PL emission transition of Nd3+ ions located at 1055 nm were increased with elevated inclusion of Ag NPs up to 0.6 mol %. The outcomes instantiate that the inclusion of Ag NPs to the optimized glass composition by 0.6 mol% making it as a beneficial host for optical amplifier and laser functionalities.

Lightweight carbon fiber hybrid film for high-efficiency electromagnetic interference shielding and electro/photo-thermal conversion applications

Enormous electromagnetic pollutions emerge with the rapid development of electronic technique, high-performance electromagnetic interference (EMI) shielding composites are greatly desired to protect human and precision instruments from electromagnetic interference. Here we fabricated a lightweight, porous carbon fiber felt/Ag/polydimethylsiloxane (CFF/Ag/PDMS) composite film via electroless plating and dip-coating method. The obtained homogenously distributed Ag nanoparticles on the surface of carbon fibers and the porous structure of CFF endow the film with excellent electrical conductivity and superior EMI shielding effectiveness (EMI SE). The maximum electrical conductivity and EMI SE value of the composite film with a thickness of 0.21 mm reach 540.9 S/cm and 105 dB at 8.2–12.4 GHz (X-band), respectively. Benefitting from the encapsulation of PDMS, the composite film exhibits outstanding corrosion resistance and oxidation resistance. Particularly, the composite film also exhibits excellent electro/photo-thermal conversion effect with outstanding heating controllability, cyclic stability, which shows great potential in 5 G communication technology and thermal management.

Improved Optical Efficiencies of Perovskite Thin Film Solar Cells by Randomly Distributed Ag Nanoparticles

Improved Optical Efficiencies of Perovskite Thin Film Solar Cells by Randomly Distributed Ag Nanoparticles

Calibration Strategy to Size and Localize Multi-Shaped Nanoparticles in Tissue Sections Using LA-spICP-MS.

In the field of nanotoxicology, the detection and size characterization of nanoparticles (NPs) in biological tissues become increasingly important. To gain information on both particle size and particle distribution in histological sections, laser ablation and single particle inductively coupled plasma-mass spectrometry (LA-spICP-MS) was used in combination with a liquid calibration of dissolved metal standards via a pneumatic nebulizer. In the first step, the particle size distribution of Ag NPs embedded in matrix-matched gelatine standards introduced via LA was compared with that of Ag NPs in a suspension and nebulizer-based ICP-MS. The data show that the particles remained intact by the ablation process as confirmed by transmission electron microscopy. Moreover, the optimized method was applied to CeO2 NPs that are highly relevant for (eco-)toxicological research but, unlike Ag NPs, are multi-shaped and have a broad particle size distribution. Upon analyzing the particle size distribution of CeO2 NPs in cryosections of rat spleen, CeO2 NPs were found to remain unchanged in size over 3 h, 3 d, and 3 weeks post-intratracheal instillation, with the fraction of smaller particles reaching the spleen first. Overall, LA-spICP-MS combined with a calibration based on dissolved metal standards is a powerful tool to simultaneously localize and size NPs in histological sections in the absence of particle standards.

Well-dispersed titanium dioxide and silver nanoparticles on external and internal surfaces of asymmetric alumina hollow fibers for enhanced chromium (VI) photoreductions

Heterogenous photocatalysis is a suitable alternative for wastewater treatment. The supporting of the solid catalyst in a porous material is suggested to facilitate catalyst recovery and reuse. Here we propose for the first time the evaluation of supporting silver (Ag)-decorated titanium dioxide (TiO2) catalysts on internal and external surfaces of alumina hollow fibers with asymmetric pore size distribution. The produced catalysts were considered for Cr(VI) photoreductions. The ultrasound-assisted process potentialized the distribution of Ag nanoparticles on the TiO2 surface. The loading of Ag nanoparticles at concentrations greater than 5 wt% was necessary to improve the TiO2 activity for Cr(VI) photoreduction. The loading of Ag nanoparticles at 30 wt% improved the Cr(VI) photoreduction of the single TiO2 catalyst from 40.49 ± 0.98 to 55.00 ± 0.83% after 180min of reaction. Suspended and supported Ag-decorated TiO2 catalysts achieved total Cr(VI) photoreduction after 21h of reaction. The adjusted reaction rate constant with the externally supported Ag-TiO2 catalyst was 3.57 × 10-3 ± 0.18 × 10-3min-1. Similar reaction rate constants were achieved with suspended and internally supported catalysts (approximately 2.70 × 10-3min-1). After 10 sequential reuses, all catalysts presented similar Cr(VI) photoreductions of approximately 66%. Nevertheless, the use of the externally supported catalyst is suggested for Cr(VI) photoreductions due to its superior catalyst activity at least in the first reuse cycles.

Polydopamine microcapsules loaded Ag nanoparticles for catalytic reduction of organic pollutants

We demonstrate a simple approach for fabricating polydopamine microcapsules decorated with silver nanoparticles (Ag@PDA MCs) as highly efficient catalysts for water purification. Polydopamine microcapsules (PDA MCs) were formed on the MnCO3 template from self-polymerization and the removal of template under mild EDTA solution, followed by in situ reduction of Ag+ by PDA and growth of monodispersed Ag nanoparticles. Under optimized conditions, the Ag@PDA MCs exhibits 41.56 wt% of Ag loading contents and superior catalytic performance for the degradation of organic pollutants with rate constant of 2.93 min-1 for methylene blue and 1.03 min-1 for 4-nitrophenol. The excellent catalytic activity can mainly be ascribed to high surface roughness of microcapsules, high Ag loading ratio, and uniform distribution of Ag nanoparticles. In addition, this catalyst can be recycled for five times with degradation efficiency higher than 98%. The Ag@PDA MCs possessed fast reduction rate, high catalytic activity, and good recyclability as well as facile preparation and easy separation, showing great potential for the application in wastewater treatment.

Fabrication of Gyroid‐Structured Metal/Semiconductor Nanoscaffolds with Ultrasensitive SERS Detection via Block Copolymer Templating

AbstractSurface‐enhanced Raman scattering (SERS) is a label‐free and powerful technique for monitoring dynamic molecular processes with high sensitivity and reproducibility. SERS has diverse applications in medicine, molecular science, biology, and chemical sensing. In this study, a template‐based approach to create an ultrasensitive SERS‐active substrate is proposed which involves combining nanostructured semiconductors and noble metals. A nanoporous polymer obtained from hydrolyzed gyroid‐forming polystyrene‐block‐poly(l‐lactide) (i.e., PS‐b‐PLLA) is used as a template for Ag reduction and TiO2 sol–gel reaction. After calcination to remove the polymeric template, TiO2 nanoscaffolds appear as self‐supporting 3D nanoobjects with homogeneously and closely distributed Ag nanoparticles, providing a high density of regions with intense local field enhancement (hotspots). Rhodamine 6G molecules are used as probe molecules to demonstrate the SERS performance, revealing a markedly high average enhancement factor of up to 1014. The intrinsic photocatalytic properties of TiO2 can degrade target organic chemicals for the self‐cleaning and reproduction of SERS‐active substrates. Moreover, a simple hydrazine reduction‐based approach is applied for the formation of regenerated Ag/TiO2 nanoscaffolds to reduce the use of Ag‐based SERS‐active substrates, decreasing the costs associated with relevant industrial processes.

Electrochemical synthesis of Co/Ni bimetal-organic frameworks: A high-performance SERS platform for detection of tetracycline

Surface-enhanced Raman scattering (SERS) enables food contaminants monitoring become facile and efficient. Herein, a facile strategy of integrating three-dimensional Ni form with Co/Ni bimetal-organic frameworks combining Ag nanoparticles via electrochemical synthesis method was proposed to develop a high-performance SERS substrate (CoNi-ZIFs@Ag@NF) for efficient detection of tetracycline. The flexible Ni foam (NF) acted as scaffold which can contribute to dramatically enhancing intrinsic electrical conductivity and endowing prepared substrate with high stability and uniform distribution of Ag nanoparticles. Furthermore, the pre-concentration effect of CoNi-ZIFs@Ag@NF for target molecules enhanced SERS performance dramatically. Besides, tetracycline was sensitively detected using CoNi-ZIFs@Ag@NF with low limit of detection (1.0 × 10-11 M) and wide linear detection range (10-10 – 10-5 M) in aqueous solution. Also, the satisfactory recovery (94.45 – 114.25 %) was realized with less than 6.78 % of RSD in real samples. This method would provide a potential and high-performance substrate for SERS monitoring of tetracycline in food and environment.

Microstructure evolution and highly sensitive surface enhanced Raman scattering properties of self-formation dual-scale Ag nanoparticles/ Ag-Zr alloy film

• Simple method was proposed to prepare monodisperse Ag particles/Ag-Zr films. • Ag nanoparticles (NPs) directly formed on the surface of as-deposited Ag-Zr films. • Size, number and nanogap of Ag NPs are sensitive to Ag-Zr film thickness. • Ag NP/Ag-Zr granular film displays effective Raman enhanced properties. Ag-22%Zr alloy films with different thicknesses were fabricated on flexible polyimide substrate by co-sputtering method. It is interested in finding that a lot of Ag nanoparticles are spontaneously formed on the as-deposited Ag-Zr films at room temperature. The phase, crystal structure, particle number and size, and surface enhanced Raman scattering (SERS) properties of as-deposited and annealed Ag-Zr alloy films were characterized by X-ray diffraction, high resolution transmission electron microscope, field emission scanning electron microscope and Raman spectrometer, respectively. Results show that Zr grains dispersed around Ag grains and had a coherent growth relation with Ag grains in the alloy film. Dual scale Ag nanoparticles were formed on the annealed Ag-Zr alloy films without template. An intense SERS effect was obtained by covering the Ag layer on the Ag-Zr alloy films. The SERS substrate showed good repeatability and revealed high sensitivity of enhancement factor with the detection limit concentration of Rhodamine 6G as low as 5 × 10-15 mol/L. It was demonstrated that the nanogaps between Ag nanoparticles behaved as hot spots, and thus enhanced local electromagnetic fields substantially. Furthermore, densely and uniformly distributed Ag nanoparticles enlarged the surface roughness and the surface area, resulting in further enhanced Raman signals.