Silver Ammonia Complex Research Articles

Low-temperature sintering of silver-ammonia complex organic composite ink shows high conductivity for humidity sensors

The development of flexible electronic devices is faced with the challenge of difficult fabrication of complex functional structures on flexible substrates. In this paper, a high viscosity ink of silver-ammonia complex was developed based on the reductive ink principle. Using the electrohydrodynamic direct writing, composite fiber patterned printing was achieved on a flexible substrate. By low-temperature sintering of precursor fibers for reduction, a dense silver structure was formed on the surface, resulting in the formation of Ag/PEO conductive fibers. This approach avoided the high temperature damage to the flexible substrate and the adhesion of materials, while demonstrating good conductivity. The Ag/PEO conductive fibers exhibited different sensitivities to H2O molecules in low, medium, and high humidity environments, which were used to design a flexible Ag structure humidity sensor (ASHS) as a functional material. The ASHS showed a linear response relationship and a fast response speed in an environmental humidity range of 11 % to 75 %RH, enabling real-time monitoring of human respiration. This study demonstrates a promising application prospect of the silver-ammine complex ink in the field of flexible electronic devices.

Durable cellulose paper by grafting thiol groups and controlling silver deposition for ultrahigh electromagnetic interference shielding

Electromagnetic interference (EMI) shielding paper with durability and high effectiveness is of significant importance to long-term service for preventing EMI pollution. Herein, we report a practical method for preparing cellulose paper/Ag composite with outstanding durable and ultrahigh EMI shielding performance by electroless silver plating. The silver deposition process, the surface morphology, the silver content and conductivity of the composite can be controlled by varying the amount of N-acetyl-L-cysteine (NAC) grafted onto the cellulose fibers and ammonia amount for silver-ammonia complex formation. Moreover, the grafted NAC with thiol groups on cellulose can enhance the adhesion between silver and cellulose paper, meanwhile, NAC as the reducing agent can result in a more complete flower-shaped silver structure and reducing the reflection of electromagnetic waves in silver layer. The composite exhibited excellent conductivity, EMI shielding effectiveness (SE) up to 106 dB and outstanding durability. After 10,000 bending times and 60 abrasion cycles respectively, the electrical resistance of the composite only increased from 0.030 Ω/sq. to 0.041 Ω/sq. and 0.050 Ω/sq., and the EMI SE decreased to 102 dB and 105 dB.

Soluble Soybean Polysaccharide/Carrageenan Antibacterial Nanocomposite Films Containing Green Synthesized Silver Nanoparticles

This study aimed to develop nanocomposite films based on a soluble soybean polysaccharide (SSPS), carrageenan (CG), and green synthesized silver nanoparticles (AgNPs) by a solution casting technique. AgNPs were obtained by reducing a silver–ammonia complex using a SSPS as both a stabilizing and reducing agent, which was confirmed by UV–vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy, and X-ray photoelectron spectroscopy. CG was introduced into the SSPS/AgNP matrix as a reinforcing component to strengthen the nanocomposite films. The results indicate that the addition of CG led to significantly enhanced mechanical properties, thermal stability, and water resistance of the films. The XRD and Fourier transform infrared spectroscopy results reveal strong interactions between AgNPs and polysaccharide chains. Compared with the SSPS/CG films without AgNPs, the SSPS/CG/AgNP nanocomposite films exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus. The results suggest that the SSPS/CG/AgNP antibacterial nanocomposite films have great potential in food and pharmaceutical packaging applications.

A novel Ag2SO3 microcrystal substrate for highly sensitive SERS sensing of multifold organic pollutants

Toxic organic pollutants have a severe impact on the environment as well as the living organisms around the world. Surface-enhanced Raman spectroscopy (SERS) is considered to be one of the advanced sensing methods for the ultrasensitive detection of organic pollutants. Herein, a novel octahedral Ag2SO3 microcrystal was synthesized using the silver-ammonia complex precipitation method for the detection of herbicide (4-chlorophenol) and synthetic dyes (sunset yellow and methylene blue dye). Ag2SO3 microcrystal exhibits superior sensitivity with an enhancement factor (EF) in the order of ~108. The large surface area with a rough octahedral morphology of Ag2SO3 favors the formation of abundant hotspots. The as-prepared Ag2SO3 also possesses excellent recyclability property via light irradiation attributed to the chemical enhancement mechanism. The capability of Ag2SO3 for the detection of 4-CP against interference in river water and honey was also investigated. It is assumed from the results that Ag2SO3 microcrystal is a promising substrate for reusable SERS applications.

Study on the mechanism of forming silver nanoparticles on micron-scale flake silver powder

Due to the high conductivity and stability of silver, silver ink has been widely used in the field of printed electronics. However, since mechanical strain would cause the contact between key particles to be broken. Recently, higher requirements have been put on the bending resistance of silver paste. In this experiment, by preparing Ag NPs: Ag Flakes composite materials of 20:80 and 30:70 respectively, a new method for preparing stable modified flake silver powder is proposed, and the attachment and growth methods of Ag NPs reduced on micron flake silver powder is discussed. Flake silver powder, dispersant and reducing agent are added to the silver-ammonia complex, and the nano-silver particles are reduced on the flake silver powder by controlling the reaction conditions. When Ag+: Ag Flakes in the solution is 30:70, there is a clear interface between the silver particles and the silver flakes, and the size distribution range is between 10 and 100 nm; when Ag+: Ag Flakes is 20:80, the distance between the nano-silver particles and the silver plate crystal plane is about 0.222 nm and 0.260 nm, these spacings represent the (1–12) and (004) planes of Ag, respectively. The reduced silver particles grow on the surface of the silver sheet, the size is about 5 ∼ 60 nm, and form a sheet-point combination of shaped silver powder, which can be used to make conductive silver paste with cost and performance competitiveness. The reaction can be completed at room temperature (5 ∼ 25 °C) and atmospheric pressure (80 ∼ 100 kPa), the operation is simple, the reaction time is short, and it has a positive effect on the commercial production of printable highly conductive silver paste.

Flow synthesis of silver nanoshells using a microreactor

Silver nanoshells have wide-ranging applications spanning from catalysis to bio-sensing because of their unique optical and chemical properties. They are synthesized through a seed-mediated growth process, in which surfaces of the core particle are decorated with metal seeds followed by the growth of silver. However, a typical synthesis is a time-consuming batch-process which creates inhomogeneity in the shell structures. Hence, it is required to establish a quick, simple, and robust synthetic method. Using a central collision type microreactor instead of a batch reactor is advantageous because of its large surface to volume ratio and rapid mixing. In this study, we synthesize silver nanoshells by using such a microreactor and investigate the effects of the molar ratio of ammonia to silver ion, the types of reducing agents, and the addition of polyvinylpyrrolidone (PVP) on the complete nanoshell formation. Our experiments demonstrate that a large molar ratio of ammonia to silver ion is required to form silver-ammonia complexes and regulate the reducing power of reductants to cover the core particles with silver. Formaldehyde, due to its weaker reducing power, is found to be a more suitable reducing agent than ascorbic acid. PVP molecules serve not only as a stabilizer but also as a facilitator to help smooth shell growth. Most importantly, the use of the microreactor is critical to the formation of complete silver nanoshells.

Size Control Synthesis of Monodisperse, Quasi-Spherical Silver Nanoparticles To Realize Surface-Enhanced Raman Scattering Uniformity and Reproducibility.

In this work, we reported the synthesis of monodisperse, quasispherical Ag nanoparticles (NPs) with sizes of 40-300 nm by using ascorbic acid reduction of a silver-ammonia complex onto preformed, 23 nm Ag-NP seeds in the aqueous solution with an optimal pH of about 9.6 at room temperature. The as-prepared Ag NPs with such a large size span (from 40 to 300 nm) and high quality by one-pot seeded growth method are reported for the first time to the best of our knowledge. It is found that the key in the present seed-mediated growth method is to introduce a proper amount of ammonia water for the formation of a stable complex with a silver precursor (silver-ammonia complex) while maintaining the pH value of the growth solution simultaneously. By using rhodamine 6G molecules as probes, the surface-enhanced Raman scattering (SERS) activities of the as-prepared Ag NPs in ethanol solution are highly dependent on the sizes of Ag NPs at the fixed 633 nm laser and at the fixed particle number, which show a volcano-like curve. Moreover, 125 nm Ag NPs bear the largest SERS activity among them. Furthermore, Ag NPs with narrow distributions in shape and size (say, less than 10%) can achieve the uniformity and reproducibility of their SERS signals in solution; their relative standard deviations can be as low as 5% in space and temporal scale.

In My Element: Silver

The In My Element series celebrates the personal accounts from Chemistry – A European Journal Editorial Board members for the 2019 International Year of the Periodic Table. In this contribution, Younan Xia gives his story on silver. Silver (Ag) is my favorite chemical element due to its broad spectrum of unique properties and applications. Although a silver medal may not be as valuable as a gold medal, silver easily beats gold in an array of applications. Silver has the highest electrical and thermal conductivities among all metals. Since ancient times, the antimicrobial capability of silver was utilized to purify water, preserve fresh milk, and treat wounds. Before digital cameras came of age, silver-based photographic films were everyday commodities. Silver is also an effective catalyst for oxidation reactions as molecular oxygen can adsorb and dissociate into atomic oxygen on its surface under ambient conditions. In fact, silver is the only catalyst capable of converting ethylene to ethylene oxide (on a scale of 20 million tons in 2009!). Oh, did I mention that silver is probably the best material for the production of shiny mirrors? The last but not least, the abundance of silver in Earth's crust is much higher than that of gold (79 vs. 3.1 ppb) so the price of silver is always a small fraction of that of gold ($17 vs. $1299 per oz.). Silver is also my lucky metal. Since 2001, my group has worked on the development of methods for the colloidal synthesis of silver nanocrystals with controlled shapes in an effort to tailor their surface plasmon resonance properties. We began with the silver mirror reaction, in which a silver ammonia complex is mixed with an aldehyde compound for immediate reduction and thus formation of a shiny mirror on the surface of the container (see the photo, left panel). With the addition of a polymer stabilizer, we could use the same reaction to produce a stable suspension of silver nanoparticles. The suspension displayed a yellow color (see the photo, right panel) because of the surface plasmon resonance peaked at 400 nm. In an effort to better control the reduction kinetics, we later switched to polyol reduction, in which a polyol such as ethylene glycol is thermally oxidized to glycoaldehyde. Since the reductant can be generated in situ and then consumed to maintain a relatively stable concentration in the reaction solution, we were able to synthesize silver nanocrystals with controlled shapes and facets, including cubes, octahedrons, cuboctahedrons, bipyramids, bars, rods, and wires. These novel nanocrystals have opened up a world of opportunities for applications in areas ranging from catalysis to plasmonics, photonics, and surface-enhanced Raman scattering, as well as fabrication of touchscreens, solar cells, flexible electronic devices, and metamaterials. In addition, our technology on silver nanowires has been commercialized by various companies for the production of flexible, transparent, and conductive electrodes. Photographs of (left) a silver mirror and (right) a colloidal suspension of silver nanoparticles. Position Brock Family Chair Professor and GRA Eminent Scholar E-mail [email protected] Homepage http://nanocages.com Education B.S (University of Science and Technology of China, 9/1982 to 7/1987, Hefei, Anhui, P. R. China) M.S. (9/1991 to 5/1993, Alan G. MacDiarmid, University of Pennsylvania, Philadelphia, PA, USA) Ph.D. (9/1993 to 8/1996, George M. Whitesides, Micro- and Nanofabrication Based on Microcontact Printing and Replica Molding, Harvard University, Cambridge, MA, USA) Postdoctoral Fellow (8/1996 to 7/1997, George M. Whitesides, Harvard University, Cambridge, MA, USA) Awards MRS Medal (Materials Research Society, 2017); ACS National Award in the Chemistry of Materials (American Chemical Society, 2013); NIH Director's Pioneer Award (National Institutes of Health, 2006); Camille Dreyfus Teacher Scholar (2002); David and Lucile Packard Fellow in Science and Engineering (2000); Sloan Research Fellow (2000); CAREER Award (National Science Foundation, 1999); Victor K. LaMer Award (American Chemistry Society, 1999); New Faculty Award (Camille and Henry Dreyfus Foundation, 1997) Research interests Nanocrystals, electrospinning, self-assembly, colloid science, catalysis, plasmonics, nanomedicine, regenerative medicine Hobbies Reading, cooking, table tennis

Synthesis and characterization of silver-loaded mesoporous alumina antibacterial agents by hydrothermal and adsorption methods

In view of the compatibility between carriers of antimicrobial agents and ceramic glaze, mesoporous alumina was employed as the carrier of silver ions and silver-loaded mesoporous alumina was synthesized by hydrothermal and adsorption methods. The liquid medium microdilution method and the spread plate methods were studied to evaluate antimicrobial efficiency of silver-loaded mesoporous alumina. \(\hbox {N}_{2}\) adsorption/desorption, HRTEM images and low-angle X-ray diffraction experiment prove the existence of fine mesoporous structure of mesoporous alumina and silver-loaded mesoporous alumina. The chelation of ammonia can improve the adsorption capacity of silver nitrate on mesoporous alumina and adsorption capacity increases by 18 times in the presence of ammonia. The adsorption behaviour of silver nitrate can be described by a multilayer adsorption isotherm of BET and the adsorption principle of silver nitrate on mesoporous alumina is multilayer adsorption in the presence of ammonia. The surface area, pore volume and pore-size distribution of silver-loaded mesoporous alumina are obviously smaller than those of mesoporous alumina due to the blockage of channel by silver-ammonia complex. The antibacterial test results indicate that silver-loaded mesoporous alumina have favourable antibiotic property and MIC \(\le \) 240 \(\upmu \hbox {g}\) \(\hbox {ml}^{-1}\) against Escherichia coli, Staphylococcus aureus and Salmonella. The diameter of inhibition zone of silver-loaded mesoporous alumina is 26 mm against Escherichia coli, 24 mm against Staphylococcus aureus and 22 mm against Salmonella enterica.

High-performance flexible all-solid-state supercapacitor constructed by free-standing cellulose/reduced graphene oxide/silver nanoparticles composite film

A 400-μm-thick free-standing and flexible cellulose/RGO/AgNPs composite film was fabricated by chemical reduction of cellulose/GO/AgNPs film with hot hydrazine vapor, which was obtained via the reaction of GO with silver–ammonia complex in the presence of cellulose fibers, followed by dewatering with assistance of filtration. The 400-μm-thick cellulose/RGO/AgNPs film was systematically characterized and found to be conductive enough with sheet resistance of merely 0.17 Ω sq−1 for direct use as electrode. When measured in a three-electrode setup, such flexible electrode exhibited outstanding supercapacitive performances with the highest areal specific capacitance of 1242.7 mF cm−2 (corresponding to 31.1 F cm−3), excellent rate capability and remarkable cycling stability with the capacitance retention of 99.6% after extensive charge/discharge at a high current density of 60 mA cm−2 for more than 10,000 cycles. Furthermore, a symmetric flexible all-solid-state supercapacitor cell of cellulose/RGO/AgNPs//cellulose/RGO/AgNPs was assembled. It delivered the maximum areal specific capacitance of 683.8 mF cm−2 (corresponding to 8.6 F cm−3), possessed desirable rate capability, showed no substantial variation of supercapacitive behavior when being bent, and offered the highest areal energy density of 95.0 μWh cm−2 (corresponding to 1.19 mWh cm−3), which outperformed that of many existing graphene-based symmetric flexible supercapacitors and lots of asymmetric flexible supercapacitors. The impressive electrochemical properties and facile preparation process of cellulose/RGO/AgNPs film make it a promising candidate for constructing next-generation high-performance flexible energy storage devices.

In situ growth of cube-like AgCl on montmorillonite as an efficient photocatalyst for dye (Acid Red 18) degradation

AgCl was incorporated with clay montmorillonite to improve the individual catalytic or adsorption performance. A green method was proposed to synthesize AgCl/montmorillonite composite by intercalating silver-ammonia complexes into the interlayers of montmorillonite followed by reacting with HCl vapor to in situ form AgCl particles on montmorillonite. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscopy, transmission electron microscope, Brunauer–Emmett–Teller analysis, X-ray photoelectron spectra, and UV–vis diffuse reflectance spectrum. It was shown that AgCl not only intercalated into the interlamination of montmorillonite but also anchored on its exterior surfaces. AgCl on clay surface was cube-like particles, which were dominated by the higher activity of {1 0 0} planes. The photocatalytic activity of AgCl/montmorillonite (AgCl-Mt) composites were evaluated by degradation of azo dye Acid Red 18 (AR18) under UV-irradiation. AgCl in AgCl-Mt composites had an optimum amount. When 3CEC of silver-ammonia was used to prepare [Ag(NH3)2]+-exchanged Mt, the obtained 3AgCl-Mt had the best activity. The degradation of 50 mL AR18 at pH 6 with 1 g L−1 of catalyst only needed 10 min. The low pH and dye concentration, and high catalyst loading favored the removal of dye. Moreover, the superoxide radicals and holes were found to be major reactive species responsible for the photocatalytic degradation of AR18. PL revealed that besides reducing the aggregation of AgCl and tailoring morphology of AgCl, montmorillonite also suppressed the combination of photogenerated electron-hole pairs, and thus enhanced the photocatalytic activity and stability. This study may offer an efficient approach for fabricating silver-halide-based composite photocatalysts for environmental cleanup.

Synergistic Ag/TiO2-N photocatalytic system and its enhanced antibacterial activity towards Acinetobacter baumannii

The hybrid Ag/TiO2-N photocatalyst was prepared via a supercritical solvothermal process in ethanol fluid. The simultaneous achievement of reduction of Ag+ ions and N-doping in silver-ammonia complex solution led to the uniform distribution of Ag nanoparticles stably combined with the surface of TiO2-N substrate. As a result, the visible-light photocatalytic inactivation of Acinetobacter baumannii was facilitated via the enhanced visible light harvesting and the high separation efficiency of photo-induced charge carriers. By means of the main active species of O2− radical, the synergistic effect of Ag nanoparticles and TiO2-N could induce the structure change of bacteria with the leakage of K+ ions as well as the mineralization of cell membrane with the elimination of self-repair function, leading to the final cell death. In comparison, the bactericidal activity of Ag nanoparticles and TiO2-N under UV light irradiation was due to the intrinsic efficiency and the high light harvesting, respectively. The photothermal effect of Ag nanoparticles in the near-IR light region could be possibly remained by TiO2-N substrate to achieve the antibacterial activity. Furthermore, Ag/TiO2-N photocatalyst played great bactericidal effect for kinds of bacteria, implying the applicable future to the medical disinfection.

A novel ZnO@Ag@Polypyrrole hybrid composite evaluated as anode material for zinc-based secondary cell.

A novel ZnO@Ag@Polypyrrole nano-hybrid composite has been synthesized with a one-step approach, in which silver-ammonia complex ion serves as oxidant to polymerize the pyrrole monomer. X-ray diffraction (XRD) and infrared spectroscopy (IR) show the existence of metallic silver and polypyrrole. The structure of nano-hybrid composites are characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), which demonstrates that the surface of ZnO is decorated with nano silver grain coated with polypyrrole. When evaluated as anode material, the silver grain and polypyrrole layer not only suppress the dissolution of discharge product, but also helps to uniform electrodeposition due to substrate effect and its good conductivity, thus shows better cycling performance than bare ZnO electrode does.

Preparation of concentrated stable dispersions of uniform Ag nanoparticles using resorcinol as reductant

Uniform silver nanoparticles ranging in size from 12 to 80nm were prepared by reducing silver ammonia complex with resorcinol in presence of Arabic gum. Despite the high ionic strength of the system, the precipitation process yields stable dispersions at metal concentrations as high as 4.0wt% (0.38moldm−3). Stable dispersions with higher solids concentration up to 20wt% silver (1.9moldm−3) were obtained by subjecting the ’as precipitated’ dispersions to ultrafiltration. The effects of reaction parameters (pH, concentration of reactants, metal/stabilizer ratio, and temperature) on particle size and dispersion stability are discussed and a mechanism for the reduction of silver is proposed.

Room Temperature Electrodeposition of Ag3PO4 Films

Ag3PO4 films were electrodeposited onto indium-tin oxide (ITO) coated glass through electrochemical generation of acid in a stable aqueous solution contained silver ammonia complexes and sodium phosphate at room temperature and pH 10. After the released H+ ions lower the local pH at ITO working electrode, Ag+ ions were dissociated from silver ammonia complex and then reacted with PO43− to form Ag3PO4 deposits on ITO. The morphologies of electrodeposited Ag3PO4 films depended on the applied potentials: trisoctahedral like structure obtained at 1.2 V versus Ag/AgCl and tetrahedral structure obtained at 1.6 V versus Ag/AgCl. The absorption spectra of the electrodeposited Ag3PO4 films were measured and they had direct and indirect band gaps of 2.43 eV and 1.99 eV, respectively. The electrodeposited Ag3PO4 films produced stable sensitive photocurrent in response to visible light irradiation at pH 7.

Influence of Experimental Conditions on Deposition of Silver Nanoparticles Onto Surface of Graphene Oxide / Wpływ Warunków Eksperymentalnych Na Proces Osadzania Nanocząstek Srebra Na Powierzchni Tlenku Grafenu

Present work describes the influence of silver nanoparticles precursor form as well as the impact of graphene oxide initial concentration on deposition of the silver nanoparticles onto graphene oxide. Borane dimethylamine complex (DMAB) was used as the reducing agent. It was observed that application of silver ammonia complexes as the silver nanoparticles precursor as well as alkaline solution effect in higher quantity of deposited AgNPs in comparison to deposition process with the use of silver(I) nitrate in acidic solution.

Encapsulated Silver Nanoparticles Can Be Directly Converted to Silver Nanoshell in the Gas Phase.

We report, for the first time, that an encapsulated silver nanoparticle can be directly converted to a silver nanoshell through a nanoscale localized oxidation and reduction process in the gas phase. Silver can be etched when exposed to a mixture of NH3/O2 gases through a mechanism analogous to the formation of aqueous Tollens' reagent, in which a soluble silver-ammonia complex was formed. Starting with Ag@resorcinol-formaldehyde (RF) resin core-shell nanoparticles, we demonstrate that RF-core@Ag-shell nanoparticles can be prepared successfully when the etching rate and RF thickness were well controlled. Due to the strong surface plasmon resonance (SPR) coupling effect among neighboring silver nanoparticles, the RF@Ag nanoparticle showed great SPR and SERS performance. This process provides a general route to the conversion of Ag-core to Ag-shell nanostructures and might be extended to other systems.

One-step preparation of silver–polyaniline nanotube composite for non-enzymatic hydrogen peroxide detection

A modified glassy carbon electrode with silver nanoparticles–polyaniline nanotubes (AgNPs–PANINTs) composite is used as a non-enzymatic nanobiosensor for detecting hydrogen peroxide (H2O2). The electrocatalytic activity for the reduction was strongly affected by the concentration of silver ammonia solution in the nanocomposites, with the best electrocatalytic activity observed for the composite of 6:1 volume ratios of PANI to Ag(NH3)2OH (0.04M). Field emission scanning electron microscope images and their size distribution diagrams indicated that using the silver ammonia complex instead of silver nitrate caused uniform distribution of nanometer-sized silver nanoparticles with a narrow size distribution in the composite. The corresponding calibration curve for the current response showed a linear detection range of 0.1–90mM (R2=0.9986), while the limit of detection was estimated to be 0.2μM at the signal to noise ratio of 3.

A one-pot method to prepare a ZnO/Ag/polypyrrole composite for zinc alkaline secondary batteries

A ZnO/Ag/polypyrrole (ZAP) composite was synthesized by a facile one-pot method in which silver ammonia complex ions were reduced to metallic silver using a pyrrole monomer as the reducing agent. Meanwhile, the pyrrole monomer was oxidized and formed polypyrrole.

One-step hydrothermal green synthesis of silver nanoparticle-carbon nanotube reduced-graphene oxide composite and its application as hydrogen peroxide sensor

A novel sensing composite of silver nanoparticles (AgNPs)-reduced graphene oxide (rGO)-carbon nanotube (MWCNT) was successfully synthesized by a simple one-step hydrothermal method without reducing agent. Mild reduction of GO was carried out under hydrothermal condition. While most conventional approaches make use of multistep chemical methods wherein strong reducing agents, such as hydrazine, hydroquinone, and sodium borohydride are employed, our method provides the notable advantage of a single-step reaction without employing any toxic solvent or reducing agent by providing a novel green synthetic route to produce the nanocomposites of rGO, carbon nanotube and silver. The results of X-ray diffraction (XRD) and Fourier-transform infrared transmission spectroscopy (FT-IR) confirmed the simultaneous formation of silver nanoparticles in the GO and MWCNT matrix. Field emission scanning electron microscope (FESEM) images and transmission electron microscopy (TEM) showed uniform distribution of nanometer-sized silver nanoparticles and narrow-sized MWCNT on GO sheets, which was achieved using silver ammonia complex as the precursor, instead of the commonly used silver nitrate. The composite exhibited excellent electrocatalytic activity for the reduction of H2O2 with a fast amperometric response time less than 3s. The electrocatalytic activity for the reduction was strongly affected by the concentration of silver ammonia solution in the nanocomposites, with the best electrocatalytic activity observed for the composite of 6:1 volume ratios of MWCNT–GO (3:1, v/v) to Ag(NH3)2OH (0.04M). The corresponding calibration curve for the current response showed a linear detection range of 0.1–100mM (R2=0. 9985), while the limit of detection was estimated to be 0.9μM.