Highly efficient CuxO/TiO2 catalysts: controllable dispersion and isolation of metal active species

Cu_xO/TiO₂ architectures with enhanced dispersion of the active phase are synthesized by a MOF-templated method. Such composites show excellent catalytic activity for CO oxidation.

Reduced graphene oxide-stabilized copper nanocrystals with enhanced catalytic activity and SERS properties

The as-obtained Cu/rGO hybrids possess excellent air stability, a higher catalytic efficiency to the reduction of p-nitrophenol and exhibit surface-enhanced Raman scattering activity.

High-Concentration Synthesis of Sub-10-nm Copper Nanoparticles for Application to Conductive Nanoinks

A simple, high-concentration (up to 0.6 M Cu salt) synthesis of sub-10-nm copper nanoparticles (Cu NPs) was developed in ethylene glycol at room temperature under ambient air conditions using 1-amino-2-propanol (AmIP) as the stabilizer. Monodispersed AmIP-Cu NPs of 3.5 ± 1.0 nm were synthesized in a high yield of ∼90%. Thus, nearly 1 g of sub-10-nm Cu NP powder was obtained using a one-step synthesis for the first time. It is proposed that metallacyclic coordination stability of a five-membered ring type between the Cu and AmIP causes the high binding force of Am IP onto the Cu surface, resulting in the superior stability of the AmIP-Cu NPs in a solution. The purified powder of AmIP-Cu NPs can be redispersed in alcohol-based solvents up to high Cu contents of 45 wt % for the preparation of Cu nanoink. The resistivity of the conductive Cu film obtained from the Cu nanoink was 30 μΩ cm after thermal heating at 150 °C for 15 min under a nitrogen flow. The long-term resistance stability of the Cu film under an air atmosphere was also demonstrated.

1D copper nanostructures: progress, challenges and opportunities

One-dimensional noble metal nanostructures are important components in modern nanoscience and nanotechnology due to their unique optical, electrical, mechanical, and thermal properties. However, their cost and scalability may become a major bottleneck for real-world applications. Copper, being an earth-abundant metallic element, is an ideal candidate for commercial applications. It is critical to develop technologies to produce 1D copper nanostructures with high monodispersity, stability and oxygen-resistance for future low-cost nano-enabled materials and devices. This article covers comprehensively the current progress in 1D copper nanostructures, most predominantly nanorods and nanowires. First, various synthetic methodologies developed so far to generate 1D copper nanostructures are thoroughly described; the methodologies are in conjunction with the discussion of microscopic, spectrophotometric, crystallographic and morphological characterizations. Next, striking electrical, optical, mechanical and thermal properties of 1D copper nanostructures are highlighted. Additionally, the emerging applications of 1D copper nanostructures in flexible electronics, transparent electrodes, low cost solar cells, field emission devices are covered, amongst others. Finally, there is a brief discussion of the remaining challenges and opportunities.

A green strategy to prepare metal oxide superstructure from metal-organic frameworks

Metal or metal oxides with diverse superstructures have become one of the most promising functional materials in sensor, catalysis, energy conversion, etc. In this work, a novel metal-organic frameworks (MOFs)-directed method to prepare metal or metal oxide superstructure was proposed. In this strategy, nodes (metal ions) in MOFs as precursors to form ordered building blocks which are spatially separated by organic linkers were transformed into metal oxide micro/nanostructure by a green method. Two kinds of Cu-MOFs which could reciprocally transform by changing solvent were prepared as a model to test the method. Two kinds of novel CuO with three-dimensional (3D) urchin-like and 3D rods-like superstructures composed of nanoparticles, nanowires and nanosheets were both obtained by immersing the corresponding Cu-MOFs into a NaOH solution. Based on the as-formed CuO superstructures, a novel and sensitive nonenzymatic glucose sensor was developed. The small size, hierarchical superstructures and large surface area of the resulted CuO superstructures eventually contribute to good electrocatalytic activity of the prepared sensor towards the oxidation of glucose. The proposed method of hierarchical superstructures preparation is simple, efficient, cheap and easy to mass production, which is obviously superior to pyrolysis. It might open up a new way for hierarchical superstructures preparation.

Formation of short three dimensional porous assemblies of super hydrophobic acetylene black intertwined by copper oxide nanorods for a robust counter electrode of DSSCs

In this study, we synthesized monolithic copper-oxide nanorods (CuO-NRs) and doped into active super hydrophobic acetylene black (AB) nanocrystals via a fast solvation method.

Redox reaction mediated direct synthesis of hierarchical flower-like CuO spheres anchored on electrospun poly(vinylidene difluoride) fiber surfaces at low temperatures

Flower-like CuO spheres anchored on electrospun PVDF fiber surfaces as catalytic membranes for the photodegradation of rhodamine B aqueous solutions.

Size-tunable and scalable synthesis of uniform copper nanocrystals

A facile and scalable synthetic route to uniform Cu nanocrystals with tunable sizes in the range of 20–100 nm based on an ethylene glycol-assisted synthetic method was developed.

Fast fabrication of copper nanowire transparent electrodes by a high intensity pulsed light sintering technique in air

A high intensity pulsed light technique was introduced to sinter and simultaneously deoxygenate copper nanowires into a highly conductive network.

Copper plasmonics and catalysis: role of electron-phonon interactions in dephasing localized surface plasmons

Copper metal can provide an important alternative for the development of efficient, low-cost and low-loss plasmonic nanoparticles, and selective nanocatalysts. However, poor chemical stability and lack of insight into photophysics and plasmon decay mechanisms has impeded study. Here, we use smooth conformal ALD coating on copper nanoparticles to prevent surface oxidation, and study dephasing time for localized surface plasmons on different sized copper nanoparticles. Using dephasing time as a figure of merit, we elucidate the role of electron-electron, electron-phonon, impurity, surface and grain boundary scattering on the decay of localized surface plasmon waves. Using our quantitative analysis and different temperature dependent measurements, we show that electron-phonon interactions dominate over other scattering mechanisms in dephasing plasmon waves. While interband transitions in copper metal contributes substantially to plasmon losses, tuning surface plasmon modes to infrared frequencies leads to a five-fold enhancement in the quality factor. These findings demonstrate that conformal ALD coatings can improve the chemical stability for copper nanoparticles, even at high temperatures (>300 °C) in ambient atmosphere, and nanoscaled copper is a good alternative material for many potential applications in nanophotonics, plasmonics, catalysis and nanoscale electronics.

Facile synthesis of Cu-Pd bimetallic multipods for application in cyclohexane oxidation

The synergy between Cu and Pd makes Cu-Pd bimetallic nanocrystals interesting materials for investigation. The scarcity of shapes of Cu-Pd bimetallic nanocrystals motivated us to explore highly branched structures, which may promote a wide range of applications. In this communication, we report a facile synthesis of Cu-Pd bimetallic multipods (19.2 ± 1.2 nm), on branches of which some high-index facets were exposed. Modification of reaction parameters concerning capping agents and reductant led to the formation of other shapes, including sphere-like nanocrystals (SNCs). When loaded onto TiO2, the as-prepared Cu-Pd bimetallic multipods exhibited excellent catalytic activity for the oxidation of cyclohexane by hydrogen peroxide and higher selectivity towards cyclohexanone than monometallic catalysts and SNCs/TiO2.

Facile synthesis of pentacle gold-copper alloy nanocrystals and their plasmonic and catalytic properties

The combination of gold and copper is a good way to pull down the cost of gold and ameliorate the instability of copper. Through shape control, the synergy of these two metals can be better exploited. Here, we report an aqueous phase route to the synthesis of pentacle gold–copper alloy nanocrystals with fivefold twinning, the size of which can be tuned in the range from 45 to 200 nm. The growth is found to start from a decahedral core, followed by protrusion of branches along twinning planes. Pentacle products display strong localized surface plasmon resonance peaks in the near-infrared region. Under irradiation by an 808-nm laser, 70-nm pentacle nanocrystals exhibit a notable photothermal effect to kill 4T1 murine breast tumours established on BALB/c mice. In addition, 70-nm pentacle nanocrystals show better catalytic activity than conventional citrate-coated 5-nm Au nanoparticles towards the reduction of p-nitrophenol to p-aminophenol by sodium borohydride.

Control over the size and shape of nanostructures is important for many applications but challenging, especially for bimetallic systems. Here, the authors report the size-controlled synthesis of star-shaped gold–copper nanocrystals and show their applications in catalysis and photothermal therapy.

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, Co3 O4 nanowires and nanowalls, TiO2 nanotubes, and Si nanowires) to achieve various hybrid hierarchical (CuO-ZnO, CuO-Co3 O4 , 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.

A facile one-step approach for the synthesis of uniform spherical Cu/Cu2O nano- and microparticles with high catalytic activity in the Buchwald–Hartwig amination reaction

An efficient, rapid, and additive-free protocol for synthesis of uniform spherical Cu/Cu₂O nano/microparticles and application in Buchwald–Hartwig amination reaction.

A facile and rapid route for the synthesis of Cu/Cu2O nanoparticles and their application in the Sonogashira coupling reaction of acyl chlorides with terminal alkynes

This work reports a simple, rapid and efficient protocol for synthesis of Cu/Cu₂O nanoparticles. The prepared Cu/Cu₂O nanoparticles were effectively utilized for Sonogashira coupling reaction of acyl chlorides with terminal alkynes.

Solvothermal synthesis of magnetic copper nitride nanocubes with highly electrocatalytic reduction properties

Copper nitride (Cu₃N) nanocubes prepared by an organic solvothermal approach exhibit excellent electrocatalytic activity toward the oxygen reduction reaction (ORR) and nitrobenzene reduction (NBR).

A highly efficient, ligand-free and recyclable SBA-15 supported Cu2O catalyzed cyanation of aryl iodides with potassium hexacyanoferrate(ii)

SBA-15 supported Cu₂O nanoparticles (Cu₂O/SBA-15) have been fabricated and characterized. The Cu₂O/SBA-15 nanoparticles can effectively catalyze cyanation of aryl iodides using non-toxic K₄[Fe(CN)₆] as a cyanide source.

EG-Assisted hand-in-hand growth of prism-like Cu2O nanorods with high aspect ratios and their thermal conductive performance

EG acts as a “bridge” that controls the “hand-in-hand” growth and transforms the Cu₂O wires into prism-like nanorods.

Shape-controlled synthesis and catalytic application of ceria nanomaterials

Because of their excellent properties and extensive applications, ceria nanomaterials have attracted much attention in recent years. This perspective provides a comprehensive review of current research activities that focus on the shape-controlled synthesis methods of ceria nanostructures. We elaborate on the synthesis strategies in the following four sections: (i) oriented growth directed by the crystallographic structure of cerium-based materials; (ii) oriented growth directed by the use of an appropriate capping reagent; (iii) growth confined or dictated by various templates; (iv) other potential methods for generating CeO(2) nanomaterials. In this perspective, we also discuss the catalytic applications of ceria nanostructures. They are often used as active components or supports in many catalytic reactions and their catalytic activities show morphology dependence. We review the morphology dependence of their catalytic performances in carbon monoxide oxidation, water-gas shift, nitric oxide reduction, and reforming reactions. At the end of this review, we give a personal perspective on the probable challenges and developments of the controllable synthesis of CeO(2) nanomaterials and their catalytic applications.

Facile synthesis of Cu and Cu@Cu-Ni nanocubes and nanowires in hydrophobic solution in the presence of nickel and chloride ions

A highly shape selective synthesis of Cu and Cu@Cu-Ni nanocubes and nanowires has been developed by modulating the coordination chemistry of transition metal ions with a trioctylphosphine (TOP)-Cl(-) ligand pair in oleylamine under mild organic solvent conditions. The as-prepared nanocubes have a face-centered cubic (fcc) phase and are covered by six {100} facets, whereas the as-prepared nanowires have a multi-twinned structure and grow along the [110] direction. Both the Ni(2+) and Cl(-) ions, along with TOP, play vital roles in determining the final morphology of the as-prepared nanocrystals (NCs). TOP can be used to selectively generate single-crystal seeds at the initial stage, which then grow into nanocubes in the presence of Cl(-) ions, while the absence of TOP leads to the formation of multi-twined crystal seeds that finally develop into nanowires. Moreover, Ni can be incorporated to form a Cu-Ni alloy shell over a Cu core at higher temperatures in a one-pot process, which makes diamagnetic Cu NCs magnetically responsive and has a significant influence on their optical properties.

Hollow CuO nanospheres uniformly anchored on porous Si nanowires: preparation and their potential use as electrochemical sensors

Hollow CuO nanospheres have been prepared via a reduction reaction of copper ions on porous Si nanowires combined with calcination in air and uniformly anchored on their surfaces. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize and analyze as-synthesized samples. The results reveal that Si nanowires fabricated from heavily doped Si wafer are formed with a meso-porous structure by an Ag-assisted etching approach, and Cu nanoparticles are formed and uniformly decorated on the Si nanowires through a reaction of copper ions reduced by silicon. After annealing in air, Cu nanoparticles are in situ oxidized and transformed into CuO, leading to the formation of hollow nanospheres because of the Kirkendall effect. The diameter size of as-prepared CuO hollow spheres anchored on porous Si nanowires is mainly around 30 nm. Finally, in order to illuminate the advantages of this novel hybrid nanostructure of nanosized hollow spheres supported on porous nanowires, its electrochemical sensing performance to hydrazine as an example has been further investigated. The results confirm that it is a good potential application to detect hydrazine.