As-prepared Copper Research Articles

Morphological studies, photocatalytic degradation of organic dyes and anticancer potential of copper sulfide nanoparticles prepared from bis(diallyl dithiocarbamato)copper(II) complex

Bis(diallyl dithiocarbamato)copper(II) complex was synthesized and characterized by single crystal X-ray crystallography. The molecular structure revealed dimeric copper(II) complex consisting of two copper(II) ions that coordinate two molecules of diallydithiocarbamato anions in bidentate chelating modes and the centrosymmetrically related diallydithiocarbamato anions bridges the S-atom of the adjacent chelating ligand to formed square pyramidal geometry around the copper(II) ions. Copper sulfide nanoparticles were prepared at 160 °C by thermolysis of the copper(II) complex in dodecylamine (DDA), hexadecylamine (HDA), and octadecylamine (ODA) to study the effect of capping agents on the structural morphologies, photocatalytic properties, and anticancer potential of the as-prepared copper sulfides nanoparticles. Powder X-ray diffraction patterns confirmed Cu9S5 digenite crystalline phases for CuS-DDA and CuS-HDA while CuS-ODA is covellite crystalline phase. HRTEM images showed spherical particles with particle sizes in the range 2–25 nm. The copper sulfide nanophotocatalysts are efficient for the degradation of bromophenol blue with the highest photocatalytic efficiency of 95.14 % for CuS-DDA followed by CuS-HDA with 94.52 % and 93.95 % for CuS-ODA. The anticancer potentials of the compounds showed that CuS-HDA is the most potent with IC50 values of 1.22 µg/mL against HEK293 and 28.78 µg/mL against HeLa.

Fabrication of a Janus Copper Mesh by SiO2 Spraying for Unidirectional Water Transportation and Oil/Water Separation.

Massive discharge of oily wastewater and frequent occurrence of offshore oil spills have posed an enormous threat to the socioeconomic and ecological environments. Janus membranes with asymmetric wettability properties have great potential for oil/water separation applications and have attracted widespread attention. However, existing Janus membranes still suffer from complex and costly manufacturing processes, low permeability, and poor recyclability. Herein, a novel and facile strategy was proposed to fabricate a Janus copper mesh with opposite wettability for unidirectional water transport and efficient oil/water separation. The hydrophilic side of the Janus copper mesh was prepared by coating it with Cu(OH)2 nanoneedles via a chemical oxidation method. The hydrophobic side was fabricated by coating it with hydrophobic SiO2 nanoparticles via a facile spraying method. The as-prepared Janus copper mesh showed asymmetric surface wettability, which can achieve unidirectional water transport and efficient oil/water separation with excellent recyclability, exhibiting great application potential for droplet manipulation and wastewater purification.

Liquid-Assisted Bionic Conical Needle for In-Air and In-Oil-Water Droplet Ultrafast Unidirectional Transportation and Efficient Fog Harvesting.

Learning from nature, many bionic materials and surfaces have been developed for the directional transportation of water and fog collection. However, current research mainly focuses on the self-transportation behavior of droplets in air-phase environments, rarely concerning underoil environments. Herein, in this work, a liquid-assisted bionic copper needle was fabricated for the rapid self-transportation of water droplets in air and oil environments. The water droplet can be spontaneously transported on the as-prepared bionic copper needle from the tip to the base. More importantly, the water-prewetted bionic copper needle can achieve the ultrafast unidirectional transportation of a water droplet in an oil environment, showing a maximum transport velocity of 76.2 mm/s and a transport distance over 33 mm, which were ten times higher than those reported in the previous research. Additionally, the droplet transport mechanism was revealed. The effects of the apex angle and tilt angle of the as-prepared bionic needle and droplet volume on the self-transportation behavior of water droplets were systematically investigated. The results indicated that the transport velocity of the water droplet decreased with the increase of the apex angle of the conical needle, while it increased with the increase of the droplet volume and needle tilt angle. Furthermore, the as-prepared bionic copper needle exhibited excellent fog collection performance with a single copper needle fog collecting efficiency of up to 2220 mg/h, which was 9.7 times that of the original copper needle. In summary, this work provides a simple and novel method to fabricate bionic copper needles for the directional self-transportation of water droplets in air-phase and oil-phase environments as well as efficient fog collection. It shows great application potential in the fields of microfluidics, desalination, and freshwater collection.

Preparation of a Bioinspired Conical Needle for Rapid Directional Water Transport and Efficient Fog Harvesting

Water shortages have become a serious issue that threatens the survival of humans, particularly in arid regions. Collecting fog from the air environment is an effective approach to obtaining freshwater resources. Herein, inspired by cactus spines, we fabricated a superhydrophilic conical copper needle by the combination of electrochemical etching and the SiO2 colloidal self-assembly method for water transportation and fog collection. It was found that a water film would be formed on the surface of the as-prepared copper needle once a water droplet was transported from the tip to the base, which acted as a lubricating film to reduce the frictional resistance between the following water droplets and the copper needle and promote the self-propelled movement of the droplets. As a result, the transport velocity and the longest transport distance of a single water droplet on the as-prepared copper needle were high up to 142 mm/s and 42 mm, respectively. Besides, the results reveal that the droplet transport distance decreased with the increase of apex angles, whereas it increased with the increase of droplet volume and tilt angles. Additionally, the as-prepared copper needle exhibited an outstanding water collection rate of ∼1700 mg/h for a single copper needle, which is five times that of the original copper needle. This work provides a facile and low-cost method to fabricate conical copper needles for water droplet manipulation and efficient fog collection, showing great application potential in the fields of microfluid, desalination, and freshwater collection.

PH-Responsive Flexible Copper Electrode with Switchable Wettability for Electrocatalytic Hydrogen/Oxygen Evolution Reactions and Urea Oxidation Reaction.

The development of a pH-responsive electrode with switchable wettability is of great importance in water electrolysis. Here, we designed a pH-responsive copper mesh/copolymer electrode to eliminate the adhesion of hydrogen/oxygen bubbles under high-speed water electrolysis by adjusting the wettability of the electrode surface. Furthermore, the kinetics of water oxidation and urea oxidation reactions on the as-prepared copper mesh/copolymer electrode were explored. Most noteworthy, the flexible water electrolysis performance of the as-prepared pH-responsive electrode was investigated for the first time. The results indicate that the copper mesh/copolymer electrode accelerates the hydrogen evolution reaction, oxygen evolution reaction, and urea oxidation reaction under better surface wettability, while it inhibits these reactions under poor surface wettability. The results provide insight into the development of unusual water electrolyzers with different pH electrolytes and the design of water electrolysis electrodes.

Anion-Incorporated Mg-Ion Solvation Modulation Enables Fast Magnesium Storage Kinetics of Conversion-Type Cathode Materials.

Rechargeable magnesium batteries (RMB) have emerged as one of the most promising alternatives to lithium-ion batteries due to the prominent advantages of magnesium metal anodes. Nevertheless, their application is hindered by sluggish Mg-ion storage kinetics in cathodes, although various structural modifications of cathode materials have been performed. Herein, an electrolyte design using an anion-incorporated Mg-ion solvation structure is developed to promote the Mg-ion storage reactions of conversion-type cathode materials. The addition of the trifluoromethanesulfonate anion (OTf- ) in the ether-based Mg-ion electrolyte modulates the solvation structure of Mg2+ from [Mg(DME)3 ]2+ to [Mg(DME)2.5 OTf]+ (DME = dimethoxy ethane), which facilitates Mg-ion desolvation and thus significantly expedites the charge transfer of the cathode material. As a result, the as-prepared CuSe cathode material on copper current collector exhibits a considerable increase in magnesium storage capacity from 61% (228 mAh g-1 ) to 95% (357 mAh g-1 ) of the theoretical capacity at 0.1 A g-1 and a more than twofold capacity increase at a high current density of 1.0 A g-1 . This work provides an efficient strategy via electrolyte modulation to achieve high-rate conversion-type cathode materials for RMBs. The incorporation of the trifluoromethanesulfonate anion in the Mg-ion solvation structure of the borate-based Mg-ion electrolyte enables the fast magnesium storage kinetics of the conversion-type cathode materials. The as-prepared copper selenide cathode achieved a more than twofold capacity increase at a high rate and the highest reversible capacities compared to those of the previously reported metal selenide cathodes.

An efficient visible light driven photocatalyst based on CuFe2O4/rGO nanocomposites for effective degradation of methylene blue dye

The pollution issue is getting worse at the same time that industry is growing. One of the toxic ingredients of these industrial effluents is the organic dyes. In this research, the efficiency of organic dye degradation over as-prepared copper ferrite (CuFe2O4) and the annealed copper ferrite (600ºC and 800ºC) nanoparticles loaded on the reduced graphene oxide (rGO) photocatalyst was investigated by hydrothermal method. The synthesized particles were characterized by XRD, FT-IR, RAMAN, FESEM, HRTEM, XPS, BET, UV-DRS and VSM. XRD and FESEM analysis were done to investigate structural properties, phase purity and surface morphology of prepared nanoferrite and their nanocomposites. FT-IR spectroscopic analysis was done to investigate functional groups of fabricated material. The FT-IR spectral analysis confirmed the presence of M − O (metal-oxygen) functional groups in the prepared materials. The RAMAN study confirmed the D-band and the G-band of graphene oxide present in the nanocomposites. UV-Vis-DRS study was done to evaluate the optical properties. The surface area and porosity of the nanoferrite and its nanocomposites were concluded by BET. The oxidation states of the constituent ions were confirmed by means of X-ray photoelectron spectroscopy (XPS). An active toxic and stable dye, Methylene Blue (MB) was employed as the target pollutant to evaluate the photocatalytic performance of the prepared nanocomposites. The effect of some parameters, dye concentration, pH and the catalyst concentration were studied. The cycle stability for dye degradation and reusability of the as-prepared catalysts show effective repeating activity up to 92.5% of its initial degradation efficiency of 100% even after four cycles. Moreover, the superparamagnetic property observed from VSM analysis made the nanocomposite recyclable.

Color-Tunable and Stable Copper Iodide Cluster Scintillators for Efficient X-Ray Imaging.

The search for color-tunable, efficient, and robust scintillators plays a vital role in the development of modern X-ray radiography. The radioluminescence tuning of copper iodide cluster scintillators in the entire visible region by bandgap engineering is herein reported. The bandgap engineering benefits from the fact that the conduction band minimum and valence band maximum of copper iodide cluster crystals are contributed by atomic orbitals from the inorganic core and organic ligand components, respectively. In addition to high scintillation performance, the as-prepared crystalline copper iodide cluster solids exhibit remarkable resistance toward both moisture and X-ray irradiation. These features allow copper iodide cluster scintillators to show particular attractiveness for low-dose X-ray radiography with a detection limit of 55 nGy s-1 , a value ≈100 times lower than a standard dosage for X-ray examinations. The results suggest that optimizing both inorganic core and organic ligand for the building blocks of metal halide cluster crystals may provide new opportunities for a new generation of high-performance scintillation materials.

Fabrication of Superhydrophobic Copper via Chemical Etching and Modification

Biological superhydrophobic surfaces are relatively common in nature. Inspired by the superhydrophobic feature, plentiful materials with hydrophobic surfaces have been fabricated for various purposes such as anti-corrosion, anti-icing, self-cleaning, friction reduction, and oil-water separation. In the present work, we report a scalable, simple, and rapid method to fabricate superhydrophobic film on copper substrates via a simple route including a chemical etching step in sodium persulfate and sodium hydroxide solution and followed by a modification step in stearic acid solution. The effect of the etchants concentration as well as etching time was investigated exhaustively. From the obtained results it was found that when a copper plate was etched in an etching solution with low etchant concentration, the contact angle of copper was greatly influenced by etching time. In contrast, the etching time hardly affected the contact angle of the copper plate at the high concentration of the etchants. The superhydrophobic feature of the copper surface (with a contact angle larger than 150o) was only achieved in certain fabrication conditions. The superhydrophobic copper substrates demonstrated good anti-corrosion properties. The corrosion current density of superhydrophobic copper substrates was 85 times smaller than that of pristine ones when manufactured under optimal conditions. In addition, the as-prepared superhydrophobic copper mesh was used to successfully separate toluene from its aqueous mixture. The superhydrophobic copper has great potential for applications in oil-water separation and anti-corrosion in aqueous environments.

Plowing-Extrusion Processes and Performance of Functional Surface Structures of Copper Current Collectors for Lithium-Ion Batteries

Most copper current collectors for commercial lithium-ion batteries (LIBs) are smooth copper foils, which cannot form a stable and effective combination with electrode slurry. They are likely to deform or fall off after long-term operation, resulting in a sharp decline in battery performance. What is worse is that this condition inevitably causes internal short circuits and thus brings about security risks. In this study, a process route of fabricating the functional surface structures on the surface of a copper collector for LIBs by twice-crisscross micro-plowing (TCMP) is proposed, which provides a new idea and an efficient method to solve the above problems from the perspective of manufacturing. The finite element simulation of TCMP combined with the cutting force test and morphological characterization is conducted to verify the forming mechanism of the surface structures on a copper sheet and its relationship with the processing parameters. The influence of several key processing parameters on the surface characteristics of the copper sheet is comprehensively explored. A series of functions is tested to obtain the optimal parameters for performance improvement of the current collector. Results show that the structured copper sheet with the cutting distance of 250 μm, cutting depth of 80 μm, and cutting crossing angle of 90° enables the best surface features of the current collector; the contact angle reaches 0°, the slurry retention rate is up to 89.2%, and the friction coefficient reaches 0.074. The battery using the as-prepared structured copper sheet as the current collector produces a specific capacity of 318.6 mAh/g after 50 cycles at a current density of 0.2 C, which is 132.7% higher than the one based on a smooth surface. The capacity reversibility of the sample with the new current collector is much better than that of the traditional samples, yielding a lower impedance.

Effect of Micro Nano-Structured Copper Additives with Different Morphology on Tribological Properties and Conductivity of Lithium Grease

ABSTRACT In order to explore the effect of micro nano-structured copper additives with different morphology on tribological properties and conductivity of lithium base grease, nano-sized copper sheets (denoted as Cu NSs), micro-sized copper wires (denoted as Cu MWs) and copper particles (denoted as Cu Ps) between micrometer and nanometer scale were prepared by liquid-phase chemical methods. The effects of synthetic variables such as reaction temperature, reaction time and pH value of reactant solution on the morphology of the final products were investigated. The as-prepared Cu NSs, Cu MWs, and Cu Ps were characterized by field emission scanning electron microscopy and X-ray diffraction. Their effects on the tribological properties and conductivity of lithium grease were investigated via ball-on-disk sliding tests and contact resistance measurements as well as morphology and element composition analyses of worn block surface. The experimental results show that the morphology of the product is significantly affected by the experimental conditions. This makes it feasible to fabricate copper additives with desired morphology by properly tuning the reaction conditions. Besides, the as-prepared copper additives can improve the tribological properties and conductivity of lithium base grease, because they can be adhered and deposited on rubbed steel surfaces to form boundary lubricating films consisting of cuprous oxide, cupric oxide, ferric oxide and other oxides.

Antioxidant high-conductivity copper paste for low-cost flexible printed electronics

The flexible printed electronics (e.g., wearable devices, roll-up displays, heating circuits, radio frequency identification (RFID) tags) calls for high-conductivity and low-cost materials, particularly for copper pastes. It is still a big challenge to develop reliable copper pastes for both antioxidant and high-conductivity flexible printed films and lines. In this work, an antioxidant copper paste was achieved using copper microflakes with surface passivation by formate ions and thiols, with high conductivity of 13400 S cm−1 (the same order of magnitude of silver pastes, 1.8–2.5 × 104 S cm−1). The universal applications of as-prepared copper paste in flexible printed electronics (e.g., electromagnetic interference (EMI) shielding films, anti-fog films, and RFID tags) via screen printing and curing at 170 °C under ambient atmosphere were demonstrated. The as-printed electronics showed high performance in flexibility, stability, and reliability. This work shows the great potential of anti-oxidation copper pastes in low-cost flexible printed electronics for commercial usage.

Halloysite functionalized with Cu (II) Schiff base complex containing polymer as an efficient catalyst for chemical transformation

Copper Schiff base complex with allyl functionality was prepared and reacted with amino-functionalized halloysite. The resultant compound was then reacted successively with melamine and the as-prepared copper Schiff base complex to furnish a polymeric moiety with multi copper Schiff base complex on the halloysite outer surface. The latter was then characterized by EDS, FTIR, TGA, ICP, TEM, XRD, VSM and elemental mapping analysis and subsequently applied as a catalyst for promoting one-pot reaction of aldehydes and dimedone to synthesize xanthene derivatives. The catalyst showed high catalytic activity under mild reaction condition and could be easily recovered and efficiently recycled with low Cu leaching. Notably, this protocol could be generalized to various aldehydes with different electron densities.

A simple and cost-effective new synthesis method of copper molybdate CuMoO4 nanoparticles and their catalytic performance

Nanopowders of copper molybdate, α-CuMoO 4 , were prepared through calcination of an oxalate complex in static air at 550 °C. The oxalate complex was investigated by Fourier transform infrared spectroscopy and thermal gravimetric analysis. The as-prepared copper molybdate was characterized by X-ray powder diffraction and the Brunauer–Emmett–Teller technique. Its catalytic effectiveness was verified by the oxidation reaction of methylene blue (MB) with hydrogen peroxide (H 2 O 2 ) and by the reduction reaction of para-, meta-, and ortho-nitrophenol. The prepared copper molybdate exhibited exceptionally high catalytic performance of the oxidation of methylene blue dye and of the reduction reaction of the three isomers of nitrophenol to the three corresponding aminophenol isomers. The evolution of the catalytic activity was controlled by utilizing UV-Vis absorption spectroscopy. • Copper molybdate, CuMoO 4 , nanoparticles were prepared successfully via a new and simple process, without resorting to any solvent at relatively low temperature. • CuMoO 4 nanocatalyst exhibits high efficiency for the reduction reaction of the three isomers of nitrophenol to the three corresponding aminophenol isomers. • The copper molybdate exhibits exceptionally high catalytic performance of the oxidation of methylene blue dye.

Copper oxide@cobalt oxide core–shell nanostructure, as an efficient binder-free anode for lithium-ion batteries

Here, cobalt oxide nanostructures synthesized on vertically aligned copper oxide nanowires (NWs) have been investigated as a possible anode material for Lithium-ion batteries (LIBs). Copper oxide NWs were formed by thermal oxidation of electrochemically deposited copper on the stainless steel mesh substrate. The process used allows the formation of highly dense copper oxide NWs with excellent adhesion to the conductive current collector substrate. A simple hydrothermal method was implemented for the deposition of cobalt oxide nanostructures on the copper oxide NWs. The as-prepared binder-free copper oxide@cobalt oxide NWs electrode exhibits a high initial specific capacity of 460 mAh g−1 at a current density of 148 mA g−1. The fabricated core–shell structure effectively improved the capacity of the fabricated half-cell by four times after 30 cycles, compared with bare copper oxide NWs. In addition to its straightforward and inexpensive synthesis process, the improved electrochemical performance suggests the copper oxide@cobalt oxide NWs electrode as a potential anode material for advanced LIBs.

A Non-enzymatic glucose sensor via uniform copper nanosphere fabricated by two-step method

Herein, we explored an effective way to obtain uniform copper nanoparticles by irradiating Cu2O microparticles in ethanol with a 1064 nm laser. The morphology, structure and chemical composition of as-prepared copper nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. It is interesting that the diameter of obtained spherical copper nanoparticles can be finely tuned by changing the irradiation time. Moreover, we also found that the particle size of copper nanoparticles can be reduced to ~63 nm when the irradiation time is 30 min. Inspired by the fast-developing non-enzymatic glucose sensors, the electrochemical activity of the copper nanoparticles toward glucose in alkaline media was further investigated. Notably, the electrochemical results reveal that the prepared copper nanoparticles possess a good prospect in non-enzymatic glucose sensor.

Enhanced Photocatalytic Degradation of Ternary Dyes by Copper Sulfide Nanoparticles.

We report the effect of thermolysis time on the morphological and optical properties of CuS nanoparticles prepared from Cu(II) dithiocarbamate single-source precursor. The as-prepared copper sulfide nanoparticles were used as photocatalysts for the degradation of crystal violet (CV), methylene blue (MB), rhodamine B (RhB), and a ternary mixture of the three dyes (CV/MB/RhB). Powder XRD patterns confirmed the hexagonal covellite phase for the CuS nanoparticles. At the same time, HRTEM images revealed mixed shapes with a particle size of 31.47 nm for CuS1 prepared at 30 min while CuS2 prepared at 1 h consists of mixtures of hexagonal and nanorods shaped particles with an average size of 21.59 nm. Mixed hexagonal and spherically shaped particles with a size of 17.77 nm were obtained for CuS3 prepared at 2 h. The optical bandgaps of the nanoparticles are 3.00 eV for CuS1, 3.26 eV for CuS2 and 3.13 eV for CuS3. The photocatalytic degradation efficiency showed that CuS3 with the smallest particle size is the most efficient photocatalyst and degraded 85% of CV, 100% of MB, and 81% of RhB. The as-prepared CuS showed good stability and recyclability and also degraded ternary dyes mixture (CV/MB/RhB) effectively. The byproducts of the dye degradation were evaluated using ESI-mass spectrometry.

Janus copper mesh with asymmetric wettability for on-demand oil/water separation and direction-independent fog collection

Traditional preparation methods of Janus membranes are either too complicated or cannot accurately control their characters such as surface wettability, layer thickness, and pore structure. Herein, asymmetric wettability and layer thickness on the copper mesh were successfully regulated by an interface-confined surface engineering strategy and applied for liquid manipulation. Water droplets can spontaneously infiltrate from the superhydrophobic side to the superhydrophilic side of the as-prepared Janus copper mesh (JCM), achieving unidirectional transportation. Besides, the separation efficiency of the JCM exceeds 99.2%, whether it is a combination of light or heavy oil-water mixtures. Moreover, compared to the corresponding superhydrophilic and superhydrophobic meshes, the JCM showed a 200% increase in fog collection. A fog collector with a sandwich structure was further developed, making up of a superhydrophilic inner layer and double-deck superhydrophobic external layers that always play a role of a Janus collector to allow a continuous and high-performance fog harvesting regardless of the direction of the fog flow. Overall, this work provides a new idea in the fabrication of Janus membranes, which could be extended to the transport of directional water, switchable oil/water separation, fog collection, and other fields.

Switchable bubble wettability copper mesh for underwater gas collection ablated by spatial modulated femtosecond laser

With the development of energy exploitation and drug researching, people pay more attention on underwater gas collection. Switchable bubble wettability surfaces play an important role in these areas. In this paper, a fast, flexible and efficient switchable bubble wettability copper surface processing method is reported. It is using spatial light modulated femtosecond laser sputtering and ablation, and its processing efficiency has increased several times. The laser treated copper mesh surfaces not only show reversible switching ability between underwater (super-)aerophilicity and superaerophobicity, but also can be cycled many time. Therefore, the as-prepared surface can control bubbles to pass through or block by switching wetting property. Finally, we demonstrated the underwater superaerophobic characteristic of the as-prepared copper mesh was used for gas collection and the gas intrusion pressure of the prepared copper mesh was studied theoretically and experimentally.

One-step deposition of stable superhydrophobic coatings with controllable wettability

A superhydrophobic coating was prepared on copper (Cu) foam by a one-step chemical deposition technique. The as-prepared coated copper foam displayed excellent superhydrophobicity (water contact angle of ∼153.5° and water sliding angle of ∼1°) with a typical surface micro–nano rough structure at a deposition temperature of 60°C and a deposition time of 20 min. The film was composed of cuprous sulfide (Cu2S) and copper tetradecanoate, which revealed the reaction mechanism. The as-prepared superhydrophobic copper foam maintained its superhydrophobicity under harsh environmental conditions (alkaline, weakly acidic, salty, long-term storage and mechanical abrasion). The as-prepared surface was still superhydrophobic after 600 mm abrasion, with a contact angle above 150.2 ± 0.2° and a sliding angle below 10°. Through the method of heat treatment and the modification of myristic acid, the surface achieved a rapid transition in wettability, with the contact angle maintaining stability for 20 cycles. The superhydrophobic film was repeatedly soaked in a mud–water mixture 20 times, and it remained silt-free, indicating excellent self-cleaning and antifouling features. More importantly, the modified copper foam can effectively separate a series of oil–water mixtures with high efficiency (>94%) even after five cycles. Thus, the presented superhydrophobic material with dual functionality is a promising candidate for application in efficient oil–water separation.