Synthesis Of Nanowires Research Articles

Relationship of photocatalysis with flavonoids in silver nanowire synthesis with herbal extract (Lavandula officinalis L.)

Nanoparticles with unique physiochemical properties can be produced using non-toxic precursors with phyto-nano synthesis. In this study, Nanowire (AgNW) was produced from silver nanoparticles (AgNP) reduced with Lavandula officinalis L. flower extract using the phyto-nano synthesis method. The length of the produced AgNW is 1-20 µm and its diameter is approximately 40-100 nm. Although the reduction of silver was quite fast in the light environment, it was found to be slow in the dark environment. However, the effect of darkness on AgNP stabilization and AgNW formation was quite important. In addition, it was revealed that the main physical factor that enables AgNW to elongate is the mechanics of the environment provided by the centrifuge. Optical and morphological characterization of nanoparticles was done with UV-visible spectrometry and SEM. The crystal structure of the particles was determined by XRD. Energy dispersion spectrums of nanoparticles were determined by EDS. Character and size analysis was performed by TEM. FTIR determination was performed on the extracts to guide the determination of the reduction factors in light and dark. The extracts were also determined by HPLC to give an idea about the role of flavonoid content in the Ag reduction due to light. Accordingly, it was found that aromatic ring compounds with alcoholic groups effectively reduce silver in the dark and promote AgNW formation.

Synthesis of One-Dimensional Titanium Oxide Nanowires for Polyvinylidene Fluoride Membrane Optimization

Due to their beneficial characteristics, 1D nanowires have made significant advancements in different realms due to their large surface area, unique surface chemistry, and tunable transport properties. Herein, a comprehensive study of titanium oxide nanowires from titanium (IV) isopropoxide, with the addition of CNTs in the polymeric membrane, has been conducted to form crystals. This method is quite proficient for nanowire synthetization, incorporated with CNTs and polymeric membranes. Carbon nanotubes (CNTs) were used to enhance their properties with polymeric polyvinylidene fluoride PVDF membrane. The concentration ratio of titanium oxide in PVDF membrane was 1, 3, 5, 10, and 15%. The development of titanium oxide nanowires at the nano level shaped, as the emulsion electrospinning created 1D nanowires. The use of an additive makes the membrane more conductive. FT-IR, XRD, EDS, and SEM techniques were used for size, surface geometry, crystalline nature, blend membrane, and thin film composition determination. Thermal Gravimetric Analysis (TGA) analysis shows that weight loss with temperature increases at optimum level.

Synthesis of GaN nanowires by ammoniating Ga2O3/BN

GaN nanowires were successfully prepared on Si (111) substrate through ammoniating Ga2O3/BN films deposited by radio frequency magnetron sputtering system. The synthesized nanowires were confirmed as hexagonal wurtzite GaN by X-ray diffraction, selected-area electron diffraction and Fourier transform infrared spectra. Scanning electron microscopy and transmission electron microscopy revealed that the grown GaN nanowires have a smooth and clean surface with diameters ranging from 40 to 160 nm and lengths typically up to several tens of micrometers. The representative photoluminescence spectrum at room temperature exhibited a strong UV light emission band centered at 363 nm and a relative weak purple light emission peak at 422 nm. The growth mechanism is discussed briefly.

Microwave-Assisted Hydrothermal Rapid Synthesis of Ultralong Hydroxyapatite Nanowires Using Adenosine 5'-Triphosphate.

Ultralong hydroxyapatite (HAP) nanowires are promising for various biomedical applications owing to their chemical similarity to the inorganic constituent of bone, high biocompatibility, good flexibility, excellent mechanical properties, etc. However, it is still challenging to control the formation of ultralong HAP nanowires because of the presence of free PO43− ions in the reaction system containing the inorganic phosphate source. In addition, it takes a long period of time (usually tens of hours) for the synthetic process of ultralong HAP nanowires. Herein, for the first time, we have developed an eco-friendly calcium oleate precursor microwave hydrothermal method using biocompatible adenosine 5′-triphosphate (ATP) as a bio-phosphorus source and water as the only solvent for the rapid synthesis of ultralong HAP nanowires. The controllable hydrolysis of ATP can avoid the premature formation of calcium phosphate nuclei and uncontrollable crystal growth. Microwave heating can significantly shorten the synthetic time from tens of hours required by the traditional heating to 1 h, thus achieving high efficiency, energy saving and low cost. The as-prepared ultralong HAP nanowires with high flexibility have lengths of several hundred micrometers and diameters of 10~20 nm, and they usually self-assemble into nanowire bundles along their longitudinal direction. The as-prepared ultralong HAP nanowire/chitosan porous scaffold has excellent bioactivity, good biodegradation and cytocompatibility owing to the bioactive adenosine adsorbed on the surface of ultralong HAP nanowires. It is expected that ultralong HAP nanowires will be promising for various applications in the biomedical fields, such as bone defect repair, skin wound healing, and as a drug nanocarrier.

Nanocasting synthesis and highly-improved toluene gas-sensing performance of Co3O4 nanowires with high-valence Sn-doping

Co 3 O 4 nanowires (NWs) arrays with the different valence metal-cations-doping (Zn, In and Sn) were synthesized by nanocasting method. The cations-doping hardly affects the morphology and mesoporous-structures, and all samples in bundles are composed of nanowires with the same diameter. Mesoporous-structures of all cations-doped Co 3 O 4 NWs results in a higher response to toluene gas. The different valence metal-cations-doping greatly affects the gas-sensing performance of Co 3 O 4 NWs sensors, which the response increases with the metal valence. Co 2.841 Sn 0.106 O 4 NWs sensor possesses the highest response (7.28) to 100 ppm toluene gas for the highest surface area and high-valence Sn-doping. Mesoporous-structure absorbs more oxygen to form O - and the thicker hole accumulation lay in air, while Sn-doping supplies electrons to combine holes in E V and increases the resistance in toluene gas. The high response is dominated with mesoporous-structures of all Co 3 O 4 NWs, while the gas-sensing performance could be further improved with Sn-doping.

Synergistic effect of noble metal doping and composite formation to boost the electrochemical properties of vanadium pentoxide

Herein, a hydrothermal method was used for the synthesis of V2O5 nanowires (NWs) and Ag-doped V2O5. The prepared doped material was intercalated in MXene for the preparation of an Ag-doped V2O5/MXene nanocomposite using a facile ultrasonication method. For structural and morphological confirmation, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy were used. Additionally, for electrochemical measurements, cyclic voltammetry (CV), cyclic-charge discharge (CCD), and electrochemical impedance spectroscopy (EIS) were performed. To avoid the restacking of Al-etched layers of MXene, Ag–V2O5 nanowires were intercalated. This strategy ultimately increases the conductive channels, which helps in boosting the electrochemical properties of Ag–V2O5 nanowires. To fabricate electrodes, indium tin oxide (ITO) was used as a substrate. As prepared, the Ag-doped V2O5/MXene@ITO electrode showed a significant increase in the specific capacity. For the Ag-doped V2O5/MXene@ITO electrode, the calculated specific capacitance was 875 F/g (at 1 A/g) using galvanostatic charge-discharge (GCD) data. Also, it lost 6.1% of capacitance after the 3000th cycle. Results suggest that as-synthesized Ag–V2O5/MXene nanocomposite is a potential electrode material for energy storage.

Facet‐Driven Vapor Phase Growth of Directional Tin‐Doped CdS Nanowires on Sapphire Surface for Photodetectors

Orientation‐controlled large‐area synthesis of nanowires (NWs) is key to their direct integration into circuits and devices for functional exploitation. Herein, the vapor–liquid–solid process yields planar arrays of tin‐doped CdS NWs with precise crystallographic orientation on flat and faceted sapphire surfaces. The nanopatterned catalyst and epitaxial correlation of each surface determine NWs’ exact position, yield, and orientation, while the graphoepitaxial effect steers their growth along the nanochannels. The incorporation of dopants widens the emission spectrum beyond the bandgap, which facilitates enhanced optical transport in NWs. Electron‐beam lithography (EBL) is employed to fabricate photodetector on individual NW, which demonstrates high photoresponsivity and fast response. Graphoepitaxial effect‐based assembly of highly ordered horizontal NW arrays and their facile self‐integration into devices for modern applications, including LEDs, biomedical or photoelectric sensors, photovoltaic cells, and visible span integrated optoelectronic and photonic systems, have promising prospects.

Defect-Rich and Single-Crystalline PdCu Ultrathin Nanowires Promoting Ethanol Oxidation Electrocatalysis

Developing high-performance electrocatalysts for the ethanol oxidation reaction (EOR) is greatly significant for the practical application of direct ethanol fuel cells, but it is still unsatisfactory. In this manuscript, we reported a facile aqueous synthesis of PdCu ultrathin nanowires (UNWs) as a highly active and stable electrocatalyst for EOR electrocatalysis. The synthesis relied on the columnar nucleation of PdCu alloys via co-reduction of Pd and Cu precursors in an aqueous solution with a highly hydrophobic dioctadecyldimethylammonium chloride as the structure-directing surfactant. PdCu UNWs featured ultrathin diameter (∼3.2 nm), defect-rich surface (high-index site), single-crystalline structure, and well-alloyed composition. They disclosed the remarkable mass activity of 3.02 A mgPd–1 and the good chronoamperometric and cycling stability for EOR electrocatalysis, both of which are better than its counterpart catalysts and commercial Pd/C. Mechanism studies further confirmed that PdCu UNWs had much better diffusion ability and lower activation energy based on their structural and compositional add-in synergies.

Synthesis of Ultrathin AuPt Alloy Porous Nanowires with Abundant Electrocatalytic Active Sites for Excellent Electrocatalysts

Synthesis of Ultrathin AuPt Alloy Porous Nanowires with Abundant Electrocatalytic Active Sites for Excellent Electrocatalysts

Synthesis of ZnO and CuO Nanowires by Thermal Oxidation on Metallic Substrates

In this research work, brass (Cu - 37.2 wt% Zn) and Cu (99.9 wt%) wires having diameters of 200 μm were thermally oxidized in N2 containing 5% O2, at a flow rate of 200 sccm and in the ambient atmosphere respectively, to support the growth of nanowires. The oxidation temperature was varied from 300 to 600 °C and the as-grown nanowires were characterized by field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray (EDX) spectroscope, and transmission electron microscope (TEM). Results show that ZnO and CuO nanowires are formed on brass and Cu wires, respectively. The ZnO nanowires are branched and CuO nanowires are straight with tapered morphology. ZnO nanowires having hexagonal wurtzite structure grow along the <1 1 0> directions whereas, CuO nanowires have monoclinic structure. A diffusion based stress induced model is proposed to explain the growth mechanism of the nanowires. Thermal oxidation process is a suitable platform for synthesizing ZnO and CuO nanowires, which can be used in in-situ device fabrication.

Facile one-step synthesis of PhC2Cu nanowires with enhanced photocatalytic performance.

In recent years, the research of phenylethynylcopper (PhC2Cu) in photocatalysis has attracted immense attention. However, its synthesis requires two steps extending over 9days. In this paper, the successful preparation of PhC2Cu nanowires is reported using a highly rapid and facile one-step method directly using copper acetate and phenylacetylene as raw materials and ascorbic acid as reducing agent. Thekineticstudiesindicatedthat the synthetic reaction follows a pseudo-second-order equation through electrical conductivity. Comparative studies of the crystal structures, morphologies, and optical properties of PhC2Cu prepared by the traditional two-step and the current one-step methods were conducted using XRD, SEM, UV-Vis Drs, FT-IR, Raman spectra, and photocurrent. Meanwhile, the PhC2Cu nanowires exhibited excellent photocatalytic activity to degrade methyl violet (MV) and glyphosate. This facile and rapid method dramatically improves the preparation efficiency of PhC2Cu, and the obtained PhC2Cu also shows higher photocatalytic activity. This remarkable progress enables the possibility of large-scale and efficient preparation of PhC2Cu with high photocatalytic activity, indicating their excellent application prospect in photocatalysis.

1D-2D hybridization: Nanoarchitectonics for grain boundary-rich platinum nanowires coupled with MXene nanosheets as efficient methanol oxidation electrocatalysts

Although a direct methanol fuel cell with high energy utilization efficiency and low hazardous emission has broad application prospects in various energy-related fields, the insufficient methanol oxidation activity as well as the short service life of the anode catalysts continue to hinder its large-scale commercialization. Herein, we demonstrate a convenient and robust approach for the controllable synthesis of 1D grain boundary-rich Pt nanowires strongly coupled with ultrathin Ti3C2Tx MXene nanosheets (Pt NWs/MX). Such a unique architectural design endows the heterojunction catalysts with a series of structural merits, including large accessible surface area, stable interconnected Pt networks, numerous grain boundary sites, ameliorative electronic structure, and excellent electron conductivity. Consequently, the optimized Pt NWs/MX catalyst exhibits a unique methanol oxidation performance with a large electrochemically active surface area of 105.5 m2 g−1, a high mass (specific) activity of 1621.5 mA mg−1 (1.6 mA cm−2), as well as superior long-term durability, making it more competitive than conventional Pt nanoparticle/carbon catalysts with the same Pt loading.

Enabling a novel approach to a controlled fabrication of 1D crystalline nanowires on suspended microstructures of arbitrary geometries using two direct-writing technologies

Recent progresses in additive manufacturing have inspired new technologies, such as direct laser writing technique, based on two-photon polymerization (2 PP), which complements and further enriches the nanofabrication tools portfolio. In this work, we combine 2 PP and our mask-free scanning probe assisted ‘direct-write patterning’ (DWP) method to allow for: a) the fabrication of micro-bridge structures with sub-micrometer resolution, b) selective synthesis of crystalline ZnO nanowires at predefined locations, respectively. This synergistic approach enables cantilever probe patterning of catalysts directly on suspended micro-bridges for in-situ CVD growth of nanoscale material, in a templated manner. The study reported here represents the first proof-of-concept experiments demonstrating versatile and scalable methodology, which can be applied and straightforwardly extended to grow a variety of other nanomaterials, in a controlled and selective fashion, on freestanding micro/nanoscale structures, whose size and geometry can be conveniently varied via templating of sacrificial 2 PP polymeric scaffolds. Finally, the demonstration of the possibility to integrate this new approach with the conventional lithography techniques provides a step forward to the development of the novel class of hybrid polymer-silicon-1D or -2D materials, and systems. The quality of the produced ZnO nanowire assemblies was assessed using several physical characterization methods.

Facile hydrothermal synthesis of zinc sulfide nanowires for high-performance asymmetric supercapacitor

A facile, single-step hydrothermal route is followed to prepare ZnS nanowires with large aspect ratios. The obtained ZnS nanowires deposited on nickel foam (ZnS/Ni-foam) exhibit a specific capacitance of 781 F/g at a current density of 0.5 A/g. An asymmetric supercapacitor fabricated from ZnS/Ni-foam as a positive electrode and jute derived activated carbon coated on Ni-foam (JAC/Ni-foam) as a negative electrode attains a high specific capacitance of 573 F/g at a current density of 0.5 A/g, with an accompanying high energy density of 51 Wh/kg at a power density of 200 W/kg in an extensive operating potential window of 1.2 V. In addition, the ZnS//JAC asymmetric supercapacitor reveals long-term cyclic stability, after 10,000 GCD cycles the device sustain around ∼87 % of the initial specific capacitance. These results shed enlighten a new opportunity for promising electrode materials in supercapacitors.

Propylene Glycol Directed Synthesis of Silver Nanowires for Transparent Conducting Electrode Application

Propylene Glycol Directed Synthesis of Silver Nanowires for Transparent Conducting Electrode Application

Simple Synthesis of PdAg Porous Nanowires as Effective Catalysts for Polyol Oxidation Reaction.

The development of efficient and stable Pd-based electrocatalysts is extremely important to facilitate the development of catalysts for polyol oxidation reactions. To synthesize Pd-based catalysts with excellent catalytic performance, a series of PdAg porous nanowires (PdAg PNWs) with different elemental ratios was constructed by facile synthesis using a seed-mediated method. The synthesized PdAg PNWs have a rough surface and a porous one-dimensional structure, which optimize the specific surface area and surface area of catalysts, thereby providing more active sites for catalysts. PdAg PNWs benefited from the geometric effect of porous nanowires and the synergy between Pd and Ag, showing excellent catalysis (8243.0 and 4137.0 mA mgPd-1) for the ethylene glycol oxidation reaction (EGOR) and glycerol oxidation reaction (GOR). Among them, the optimal Pd62Ag38 PNWs show the highest catalytic activity (6.0 times and 3.9 times higher than Pd/C) and stability compared with Pd57Ag43 PNWs, Pd51Ag49 PNWs, and Pd/C for EGOR and GOR. At the same time, this porous one-dimensional structure also endows PdAg PNWs with faster electron transfer capabilities than Pd/C. This work will likely provide an effective strategy for constructing cost-effective catalysts.

Lattice-mismatch-free growth of organic heterostructure nanowires from cocrystals to alloys

Organic heterostructure nanowires, such as multiblock, core/shell, branch-like and related compounds, have attracted chemists’ extensive attention because of their novel physicochemical properties. However, owing to the difficulty in solving the lattice mismatch of distinct molecules, the construction of organic heterostructures at large scale remains challenging, which restricts its wide use in future applications. In this work, we define a concept of lattice-mismatch-free for hierarchical self-assembly of organic semiconductor molecules, allowing for the large-scale synthesis of organic heterostructure nanowires composed of the organic alloys and cocrystals. Thus, various types of organic triblock nanowires are prepared in large scale, and the length ratio of different segments of the triblock nanowires can be precisely regulated by changing the stoichiometric ratio of different components. These results pave the way towards fine synthesis of heterostructures in a large scale and facilitate their applications in organic optoelectronics at micro/nanoscale.

Controllable synthesis of silver nanowires via an organic cation‐mediated polyol method and their application as transparent electrode for touch screen

AbstractAs an organic cation, quaternary ammonium salt was introduced as a control agent to synthesize silver nanowires. The important influence of quaternary ammonium salt on the preparation of silver nanowires was seriously investigated by varying the length of carbon chain and its amount. Results showed that using quaternary ammonium salt as the control agent can successfully control the growth of silver nanowires, of which the diameters ranging from 35.06 to 46.60 nm. The diameters of the as‐prepared silver nanowires tended to be smaller with a longer carbon chain. This work provides a new aspect for controllable preparation of silver nanowires. Furthermore, the as‐prepared silver nanowires were used to prepare transparent electrodes. They exhibited good optical performance with 95.6% transmittance at a low sheet resistance of 18 Ω/square, demonstrating their great potential in the application for touch screens.

Synthesis of silver sulfide nanowires: Variation of the morphology and structure

The beaded string silver sulfide nanowires (Ag2S NWs) are produced by the sulfuration reaction between silver nanowires (Ag NWs) and sodium polysulfide (Na2Sx) within the aqueous solution at room temperature. The reaction was preferentially initiated at the tip and defect of the Ag NWs, and the volume expansion occurs at the sulfurized sites due to the larger volume of silver sulfide (Ag2S) than silver (Ag). As the reaction progresses, the sulfurized area spreads around, resulting in multiple protrusion of the Ag-Ag2S hybrid nanowires. The lag reaction position to be unable to embed enough sulfur atoms due to the extrusion stress of expansion on both sides, leading to the formation of the flat bamboo joint sandwiched between bulges finally. This paper describes the structure evolution and morphology transformation of Ag NWs during the sulfuration process, and focuses on the studying of sulfuration mechanism.

Optical Properties of Colloidal Silver Nanowires.

Silver nanowires are used in many applications, ranging from transparent conductive layers to Raman substrates and sensors. Their performance often relies on their unique optical properties that emerge from localized surface plasmon resonances in the ultraviolet. To tailor the nanowire geometry for a specific application, a correct understanding of the relationship between the wire’s structure and its optical properties is therefore necessary. However, while the colloidal synthesis of silver nanowires typically leads to structures with pentagonally twinned geometries, their optical properties are often modeled assuming a cylindrical cross-section. Here we highlight the strengths and limitations of such an approximation by numerically calculating the optical and electrical response of pentagonally twinned silver nanowires and nanowire networks. We find that our accurate modeling is crucial to deduce structural information from experimentally measured extinction spectra of colloidally synthesized nanowire suspensions and to predict the performance of nanowire-based near-field sensors. On the contrary, the cylindrical approximation is fully capable of capturing the optical and electrical performance of nanowire networks used as transparent electrodes. Our results can help assess the quality of nanowire syntheses and guide in the design of optimized silver nanowire-based devices.