Solution-phase synthesis of Cu2O cubes using CuO as a precursor

We describe a facile route for the synthesis of Cu₂O cubes using CuO as the precursor and hydrazine hydrate as the reducing agent. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations indicate that the Cu₂O products are composed of cubes with an edge length of 0.7-1.2 μm. This method is surfactant-free, and well-dispersed Cu₂O cubes can be obtained through this route. The presence of small amounts of ions in reaction solution has a great influence on the morphology of Cu₂O products.     

Synthesis and photo-catalytic degradation property of nanostructured-ZnO with different morphology

ZnO nanostructures with different morphology have been successfully fabricated by a simple relative low temperature approach at 90 °C for 5 h without surfactant assistance. These structures can be easily tailed using varied concentrations of sodium hydroxide (NaOH) and different amounts of the hydrazine hydrate (N₂H₄·H₂O). X-ray diffraction (XRD) result proves the formation of ZnO with wurtzite structure. Microstructure as revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicates that the rod-like and chrysanthemum-like ZnO nanostructures contain many radial nanorods, which grow along the [0001] direction. Furthermore, the as-prepared ZnO nanomaterials exhibit high activity on the photo-catalytic degradation of typical persistent organic pollutants (POPs), indicating that they are promising as semiconductor photo-catalysts.     

A novel route for the synthesis of nanotubes and fullerene-like nanostructures of molybdenum disulfide

The paper described the synthesis of nanotubes and fullerene-like nanostructures of MoS₂ through a technically simple, rapid, and energy-efficient microwave-assisted synthesis technique, which involved the use of elemental sulfur dissolved in a mixture of monoethanolamine and hydrazine hydrate as the sulfide source. The microwave induced reaction between the molybdate with sulfide ions, in the presence of hydrazine hydrate in the reaction medium, resulted in the formation of gray colored powders of amorphous MoS₂. The as-obtained powders were calcined at 600 °C for 2 h and characterized by different techniques. HRTEM analysis of the calcined samples indicated the formation of fullerene-like MoS₂ structures when the starting solution mixture was irradiated with microwave for a period of 200 s, while on 600 s of irradiation of the same revealed the formation of folded sheets like MoS₂ nanotubes. BET surface areas of the calcined samples have been measured and a plausible reaction mechanism for the formation of nanotubes and fullerene-like nanostructures of MoS₂ has been proposed.     

Shape-controlled synthesis of single-crystalline cupric oxide by microwave heating using an ionic liquid

Cupric oxide (CuO) with leaf-like, chrysanthemum-like and rod shapes have been synthesized by microwave-assisted approach using an ionic liquid 1-n-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM]BF₄). By controlling the concentration of [BMIM]BF₄ and reaction time, shape transformation of CuO nanostructures could be achieved in a short period of time. The crystal structure and morphology of products were characterized by XRD, TG, FESEM/EDS, and TEM/SAED. A possible mechanism for the shape transformation of CuO nanostructures was proposed. In addition, UV–vis spectra were employed to estimate the band gap energies of the nanosized semiconductors.     

HEPES-mediated controllable synthesis of hierarchical CuO nanostructures and their analogous photo-Fenton and antibacterial performance

Owing to the strongly morphology and size-dependent properties of nanomaterials, developing a simple and eco-friendly approach for controlling synthesis and assembly of hierarchical CuO nanostructures plays a critical role. In this work, we successfully developed an eco-friendly and facile hydrothermal route for controllable synthesis of various morphologies CuO nanostructures, where traditional and toxic additives were replaced by biocompatible 4-(2-hydroxyethyl)-1-piperazineethane-sulfonic acid (HEPES). The growth rate and orientation of CuO nanoparticles were tuned through adjusting the concentration and pH value of HEPES. The XRD pattern, SEM, UV-DRS, and BET indicated CuO nanostructures maintained high purity and excellent crystalline nature and showed more regular morphology and size with enhanced visible light absorption. The analogous photo-Fenton assay demonstrated that the as-prepared CuO nanostructures present enhanced dye removal capability when compared with CuO synthesized in pure water. Furthermore, the antibacterial assay on S. aureus was also investigated, and CuO nanoparticles with smallest size displayed the best antibacterial performance. These results reveal that HEPES shows a remarkable influence on the possible application of as-prepared CuO nanostructures which having great potential in pollutant removal.     

Solvent-free preparation of copper ferrite microspheres composed of nanorods using a new coordination compound as precursor

This work presents a simple solvent-free route based on solid-state thermal decomposition approach to synthesize magnetic copper ferrite (CuFe₂O₄) microspheres and copper ferrite/metal oxide composites. For this purpose, [Cu(en)₃]₃[Fe(ox)₃]₂ complex (where en?=?ethylenediamine and ox?=?oxalate) was introduced as a new single-source precursor. Ferromagnetic property of the nanostructures was determined by alternating gradient force magnetometer. The effect of different ligands and temperatures on the morphology of the products was investigated. Solid-state thermal decomposition of the precursor at different temperatures in the range of 400–800?°C led to the fabrication of magnetic copper ferrites with various particle sizes. X-ray powder diffraction patterns and images of scanning electron microscopy showed formation of CuFe₂O₄/Fe₂O₃ microspheres with very smooth surfaces and CuFe₂O₄/CuO microspheres coated with nanorods by thermal decomposition of the precursor at 400 and 700?°C, respectively. The results confirmed that copper ferrite and CuFe₂O₄/CuO nanocomposites were suitable materials with appropriate performance in catalyst and photo-catalytic applications.     

Hydrogen peroxide-assisted hydrothermal synthesis of hierarchical CuO flower-like nanostructures

Hierarchical CuO nanostructures were synthesized through a hydrogen peroxide-assisted hydrothermal route in which Cu(OH)₂ was the copper source. The CuO nanostructures were composed of numerous nanobelts that radiated from the center of the nanostructure and formed a flower-like shape with a diameter of 5-10 μm. The nanobelts had lengths of 2.5-5 μm and widths of 150-200 nm. The H₂O₂ concentration directly influenced the product morphology. As the concentration of H₂O₂ increased, the length and width of the nanobelts increased and the quantity of the nanobelts decreased. The possible formation mechanism of hierarchical CuO flower-like nanostructures was presented.     

ZnO hierarchical nanostructures and application on high-efficiency dye-sensitized solar cells

Uniform hierarchical ZnO nanostructures are synthesized on a large scale based on a solution approach at low temperature. The primary ZnO hexagonal prisms are firstly produced by the reaction of Zn(NO₃)₂ with hexamethylenetetramine, and then ZnO branches grow on the primary prisms by using ethylenediamine molecules as an evocator. The morphology of the hierarchical nanostructure can be controlled conveniently by adjusting the molar ratio of [EDA]/[Zn²⁺]. The hierarchical structure provides an effective pathway for carrier transport as well as larger surface area for dye adsorption, when ZnO hierarchical nanostructures serve as photoanode materials, the solar cells show higher conversion efficiency than that of primary ZnO nanowires.     

In Situ Synthesis of CuO and Cu Nanostructures with Promising Electrochemical and Wettability Properties

A strategy is presented for the in situ synthesis of single crystalline CuO nanorods and 3D CuO nanostructures, ultra‐long Cu nanowires and Cu nanoparticles at relatively low temperature onto various substrates (Si, SiO₂, ITO, FTO, porous nickel, carbon cotton, etc.) by one‐step thermal heating of copper foam in static air and inert gas, respectively. The density, particle sizes and morphologies of the synthesized nanostructures can be effectively controlled by simply tailoring the experimental parameters. A compressive stress based and subsequent structural rearrangements mechanism is proposed to explain the formation of the nanostructures. The as‐prepared CuO nanostructures demonstrate promising electrochemical properties as the anode materials in lithium‐ion batteries and also reversible wettability. Moreover, this strategy can be used to conveniently integrate these nanostructures with other nanostructures (ZnO nanorods, Co₃O₄ nanowires and nanowalls, TiO₂ nanotubes, and Si nanowires) to achieve various hybrid hierarchical (CuO‐ZnO, CuO‐Co₃O₄, CuO‐TiO₂, CuO‐Si) nanocomposites with promising properties. This strategy has the potential to provide the nano society with a general way to achieve a variety of nanostructures.     

Synthesis and characterization of (CuO)x(ZnO)1 − x composite thin films with tunable optical and electrical properties

Mixed (CuO)_x(ZnO)_1 − x composite films have been prepared on glass substrates by a sol-gel spin coating method using copper acetate hydrate and zinc acetate dihydrate as precursors. The surface morphology and crystal structure of the films were investigated by field emission scanning electron microscopy and x-ray diffraction, respectively. It was observed that the crystal structure changed from wurtzite (ZnO) to monoclinic (CuO) as the Cu content increased from 0% to 100% in the films. UV-Vis absorption and photoluminescence measurements indicated that the optical properties can be tuned continuously from pure ZnO to pure CuO as the Cu content was increased, following the expected trends for a transition from ZnO to CuO. The resistivity of the films decreased by three orders of magnitude as Cu increased from 0% to 100%. These semiconducting composite oxides with tunable optical and electrical properties have potential applications in electronics and optoelectronics.     

Synthesis of CuO nanoflower and its application as a H<Subscript>2</Subscript>O<Subscript>2</Subscript> sensor

CuO three-dimensional (3D) flower-like nanostructures were successfully synthesized by a simple method at 100°C with Cu(NO₃)₂·3H₂O and NH₃·H₂O for 6 h in the absence of any additives. We found that NH₃·H₂O amount was critical for CuO morphology evolution. The phase analysis was carried out using X-ray diffraction (XRD) and the result confirmed that the CuO nanoflowers were single-phase. The morphological investigations by field emission scanning electron microscope (FESEM) revealed that the CuO nanoflowers were mono-dispersed in a large quantity and consisted of nanosheets. And then, CuO nanoflowers were successfully used to modify a gold electrode to detect H₂O₂ with cyclic voltammetry (CV) and amperometric (AC). It was found that CuO nanoflowers may be of great potential for H₂O₂ electrochemical sensing.     

Phase, morphology, and dimension control of CIS powders prepared using a solvothermal process

Crystalline chalcopyrite semiconductor CuInSe₂ nanostructures were prepared using a solvothermal route. Various amine organic agents were used as the solvents. Cupric chloride, indium chloride, and selenium powders were mixed in a solvent of ethylenediamine or diethylamine. Effects of reaction time, reaction temperature, solvent type, and reactant concentration were studied. The results show that through selective processing conditions, the phase, morphology, and dimensions of the obtained CIS nanostructures can be controlled.     

Flower-like CuO synthesized by CTAB-assisted hydrothermal method

Flower-like CuO nanostructures have been synthesized by cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method. Here, CuCl₂·2H₂O was used as copper raw material, and sodium hydroxide was used as precipitate. The resulting CuO powders were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). X-ray diffraction (XRD) pattern exhibited the nanocrystalline nature with monoclinic structure for the as-synthesized nanostructures. FESEM images indicated that the flower-like CuO nanostructures are composed of many interconnected nanosheets in size of several micrometres in length and width and 60–80 nm in thickness. The possible formation mechanism of flower-like CuO nanostructures was discussed.     

Rapid synthesis of TiO2 hollow nanostructures with crystallized walls by using CuO as template and microwave heating

In this paper, TiO₂ hollow nanostructures with anatase walls have been rapidly fabricated by using CuO as template and microwave heating. These TiO₂ hollow nanostructures have been characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Experimental results showed that the TiO₂ shell transformed from amorphous to anatase phase in 3 min, induced by the hot CuO core under microwave irradiation. The diameter of TiO₂ hollow nanostructures is about 50-80 nm, and the length is about 200-300 nm. The thickness of the shell is about 3 nm. This method is promising to be used to synthesize other nanomaterials with a hollow nanostructure.     

Thermal evolution of morphological,optical, and photocatalytic properties of Au–Cu2O–CuO nanocomposite thin film

Plasmonic nanocomposite thin films find exciting applications in environmental remediation and photovoltaics. We report on thermal annealing driven development of morphology, structure and photocatalytic performance of Au–Cu₂O–CuO nanocomposite thin film. Nanocomposite thin film coatings of Au–Cu₂O–CuO, prepared by radio frequency (RF) magnetron co-sputtering, were annealed at different temperatures. Thermal annealing driven evolution of morphology of Au–Cu₂O–CuO nanocomposite was studied by field emission scanning electron microscopy (FESEM), which revealed significant growth in size of nanostructures from 10 nm to 69 nm upon annealing. X-ray diffraction (XRD) together with Raman studies confirmed the nanocomposite nature of Au–Cu₂O–CuO film. UV-visible diffuse reflectance spectroscopy (UV-vis-DRS) studies showed band gap variation from 2.44 eV to 1.8 eV upon annealing at 250 °C. Nanocomposite thin film annealed at 250 °C exhibited superior photocatalytic activity for organic pollutants [methylene blue (MB) and methyl orange (MO)] decomposition. The origins of thermal transformation of morphological, optical and photocatalytic behaviour of the Au–Cu₂O–CuO nanocomposite coating are discussed.

     

Microwave synthesis of SrCO3 one-dimensional nanostructures assembled from nanocrystals using ethylenediamine additive

One-dimensional SrCO₃ nanostructures assembled from nanocrystals have been successfully synthesized by a microwave-assisted aqueous solution method at 90 °C using Sr(NO₃)₂, (NH₄)₂CO₃ and ethylenediamine (C₂H₈N₂). Our experiments show that the microwave heating time plays an important role in the size and morphology of SrCO₃. A rational mechanism based on the oriented attachment self-assembly is proposed for the formation of SrCO₃ nanostructures. The products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). This method is simple, fast, low-cost and suitable for large-scale production of SrCO₃ nanostructures with different morphologies. We expect that this method may be extended to the preparation of nanostructures of other kinds of carbonates.     

Fabrication of conductive copper-coated glass fibers through electroless plating process

A simple electroless copper plating process was employed to prepare copper-coated glass fibers with excellent conductivity. The glass fibers were pretreated by etching, sensitizing, and activating procedures. Disodium ethylenediamine tetra acetate (EDTA-2Na) and hydrazine hydrate (N₂H₄·H₂O) were employed as complex reagent and reductant, respectively. It was found that the copper deposition was greatly influenced by dosage of EDTA-2Na, concentration of sodium hydroxide (NaOH), temperature, and volume of N₂H₄·H₂O. The optimal temperature for electroless copper plating ranged from 40 to 60 °C. The composites were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy techniques. The result showed that the minimum volume resistivity of 0.0010 Ω cm was obtained for the sample with perfect copper coatings on the surface of glass fibers. This method is simple, low-cost, and large production, and can be extended to fabricate other metal-coated glass fibers with distinct conductivity.     

Microwave-assisted synthesis and characterization of flower shaped zinc oxide nanostructures

A microwave-assisted solution-phase approach has been applied for the synthesis of zinc oxide nanostructures. The synthesis procedure was carried out by using two reagents: hydrazine hydrate and ammonia. Flower shaped particles were obtained with hydrazine hydrate whereas mainly spherical agglomerated particles were observed with ammonia. The nanostructures were influenced by microwave irradiation time, reagent concentration and molar ratio of the precursors. High crystalline materials were found without the need of a post-synthesis treatment. The average crystalline size of ZnO nanostructures has been analyzed by X-ray Diffraction (XRD) pattern and estimated to be 18 nm. The presence of flower shaped zinc oxide with nanorods arranged has been confirmed from Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) micrographs. The samples were further analyzed by Fourier Transform InfraRed (FT-IR), Thermogravimetric Analysis (TGA) and photoluminescence spectroscopic techniques.     

A facile surfactant-free fabrication of single-crystalline truncated Fe3O4 cubes

Single-crystalline truncated Fe₃O₄ cubes with active basal facets have been successfully fabricated through a facile surfactant-free hydrothermal route. The presented materials were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), dynamic light scattering (DLS), selection area electron diffraction (SAED) and magnetic property measurement system (MPMS). The results showed that all products are Fe₃O₄ with face-center-cubic (FCC) structure. The morphology of Fe₃O₄ depends on the contents of hydroxide ions, hydrazine hydrate and reaction time. The well-defined truncated Fe₃O₄ cubes with active basal facets {1 0 0} were fabricated when the pH value, the hydrazine hydrate content and reaction time are 10, 10 mL and 24 h, respectively. The as-prepared Fe₃O₄ cubes exhibit excellent magnetic properties, which endow the materials with great potential applications in many fields.     

Sonochemical-assisted synthesis and characterization of CeO<Subscript>2</Subscript> nanoparticles and its photocatalytic properties

In the present study, cerium oxide (CeO₂) nanoparticles were prepared through sonochemical-assisted method, using (NH₄)₂Ce(NO₃)₆, hydrazine and ethylenediamine as precursors. Also, the effects of concentration of precursors as well as reaction time on the morphology and size of nanoparticles were investigated. The synthesized CeO₂ nanoparticles were characterized by X-ray diffraction patterns, energy-dispersive X-ray spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and diffuse reflectance spectroscopy. The results indicate that the estimated particle size of synthesized CeO₂ nanoparticles is about 20–30 nm. Furthermore, photocatalytic activities of CeO₂ nanoparticles were investigated by degradation of methylene blue under UV-light irradiation.