Copper Precursor Research Articles

Tailoring Morphology and Elemental Distribution of Cu-In Nanocrystals via Galvanic Replacement.

The compositional and structural diversity of bimetallic nanocrystals (NCs) provides a superior tunability of their physico-chemical properties, making them attractive for a variety of applications, including sensing and catalysis. Nevertheless, the manipulation of the properties-determining features of bimetallic NCs still remains a challenge, especially when moving away from noble metals. In this work, we explore the galvanic replacement reaction (GRR) of In NCs and a copper molecular precursor to obtain Cu-In bimetallic NCs with an unprecedented variety of morphologies and distribution of the two metals. We obtain spherical Cu11In9 intermetallic and patchy phase-segregated Cu-In NCs, as well as dimer-like Cu-Cu11In9 and Cu-In NCs. In particular, we find that segregation of the two metals occurs as the GRR progresses with time or with a higher copper precursor concentration. We discover size-dependent reaction kinetics, with the smaller In NCs undergoing a slower transition across the different Cu-In configurations. We compare the obtained results with the bulk Cu-In phase diagram and, interestingly, find that the bigger In NCs stabilize the bulk-like Cu-Cu11In9 configuration before their complete segregation into Cu-In NCs. Finally, we also prove the utility of the new family of Cu-In NCs as model catalysts to elucidate the impact of the metal elemental distribution on the selectivity of these bimetallics toward the electrochemical CO2 reduction reaction. Generally, we demonstrate that the GRR is a powerful synthetic approach beyond noble metal-containing bimetallic structures, yet that the current knowledge on this reaction is challenged when oxophilic and poorly miscible metal pairs are used.

Effect of different precursors on the electrochemical behavior of CuS nanostructures as electrode material for supercapacitor applications

In the present work, we synthesized copper sulfide (CuS) nanostructure using the co-precipitation technique by employing two different copper precursors such as copper nitrate, copper chloride with water as a solvent in order to investigate the effect of different precursors on the electrochemical behavior of CuS nanostructures as electrode material for supercapacitor application. X-ray diffraction analysis confirmed the pure phase (hexagonal-P63/mmc) formation of CuS nanostructures. The morphological and elemental compositional studies are done by scanning electron microscopy and energy-dispersive X-ray spectroscopy respectively. Electrochemical characterizations like cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS) were utilized to analyze the super capacitive properties of the fabricated electrode material in a three-electrode system using 2 M KOH solution as an aqueous electrolyte. The highest value of specific capacitance is found to be 346.66F/g at 2 A/g for the sample synthesized via copper nitrate precursor. Furthermore, it also displayed good cycling stability with more than 80 % retention of capacitance over 500 GCD cycles. Hence, the analysis of the result revealed that precursors play a major role in modifying the electrochemical properties.

Selective growth of graphene films on gallium-focused ion beam irradiated domains

Graphene, a single layer of carbon atoms tightly bound in a hexagonal honeycomb lattice to form a two-dimensional lattice, is a very interesting material with promising electronic, optical, chemical, and mechanical applicative potential [Geim and Novoselov, Nat. Mater. 6, 183 (2007)]. The properties of graphene make it suitable for a wide range of applications; however, its applicative future still depends on large scale technologies capable to robustly and reproducibly transfer its outstanding intrinsic properties into devices or complex structures. It must be recognized that a crucial technological problem, that still inhibits the applicability of high quality graphene material properties, is related to the patterning of this material using traditional top down instruments and lithographical methods. In this work, we will detail our investigations on applying a precise 30 keV Ga+ ion irradiation to selectively shape and modify a copper precursor surface for promoting the local growth of graphene surface domains. The morphology of these domains is investigated using scanning tunneling microscopy and spectroscopy to probe simultaneously the structural and the electronic properties at the atomic scale of the graphene films.

Impact of Cu on structural, optical, dielectric properties and antibacterial activity of TiO2 thin films

In this work, Copper-doped TiO2 thin films were synthesized on glass substrates using a sol-gel dip-coating technique with varied molar concentrations of copper precursor (1,3,5,7,9 at. wt. %). Cu affected the structural, morphological, dielectric, antibacterial, and optical properties of TiO2 films. The formation of the anatase phase was confirmed by XRD. The morphology of all synthesized thin films was spherical grains with slight aggregation. The hopping process explained dielectric characteristics that obeyed the Maxwell-Wagner model and Koop's theory. These films were ideal for high-frequency devices because of their low dielectric constant. It was observed that as Cu concentration increased, the optical band gap energy reduced, which was beneficial for improving solar cell efficiency. Cu-doped TiO2 produced the best antibacterial agent. The photocatalysts with the highest photo activities were those containing 9 wt% Cu. The increased light absorption in the UV-VIS range and the lower recombination rate of the photoinduced electron hole pair of Cu-doped TiO2 thin films were responsible for the improved photocatalytic activity. Methylene blue degraded in the presence of sunshine, making it a potential material for the treatment of water.

Preparation of Copper Nanoplates in Aqueous Phase and Electrochemical Detection of Dopamine.

Compared with gold and silver, cheap copper has attracted more attention and can potentially be applied in non-enzymatic electrochemical sensors due to its excellent conductivity and catalytic activity. In this paper, copper nanoplates were rapidly synthesized using copper bromide as the copper precursor, polyethyleneimine as the stabilizer, and ascorbic acid as a reducing agent in the presence of silver nanoparticles at a reaction temperature of 90 °C. The Cu nanoplates with an average side length of 10.97 ± 3.45 μm were obtained after a short reaction time of 2 h, demonstrating the promoting effect of an appropriate amount of silver nanoparticle on the synthesis of Cu nanoplates. Then, the electrochemical dopamine sensor was constructed by modifying a glass carbon electrode (GCE) with the Cu nanoplates. The results obtained from the test of cyclic voltammetry and chronoamperometry indicated that the Cu-GCE showed a significant electrochemical response for the measurement of dopamine. The oxidation peak current increased linearly with the concentration of dopamine in the range of 200 µmol/L to 2.21 mmol/L, and the corresponding detection limit was calculated to be 62.4 μmol/L (S/N = 3). Furthermore, the anti-interference test showed that the dopamine sensor was not affected by a high concentration of ascorbic acid, glucose, uric acid, etc. Therefore, the constructed Cu-GCE with good selectivity, sensitivity, and stability possesses a high application value in the detection of dopamine.

Fast photodetection in eco-friendly wurtzite CuInS2 nanocrystals based photodiode with a planar geometry

This study describes the optoelectronic characteristics of CuInS2 nanocrystals (NCs) in wurtzite (WZ) stoichiometry. Non-toxic CuInS2 NCs are successfully synthesized via simple solvothermal method with no secondary phases, due to proper control of copper, indium and sulfide precursors amount. Pure CuInS2 NCs based planar photodetector geometry provides a strong photo-response upon excitation from 390 nm to 950 nm optical spectra, including responsivity up to 21 AW-1, detectivity of 9.8 × 1011 Jones and response-speed of ∼ Tr/Tf = 2.32 s/4.93 s, at 950 nm wavelength. Moreover, to realize a fast response-time, a simple strategy is presented based on providing one vertical photodetector geometry in the lateral form. We designed a micro-spaced trench (channel length ∼ 40 μm) on FTO/glass substrate using CO2 laser. The device shows a noticeably fast response-time ∼ 60 ms over the whole examined spectral range, concomitant with responsivity and detectivity of 264.9 mAW−1 and 7.9 × 1010 Jones at 950 nm wavelength. The fast response-time could be attributed to the photovoltaic mode and the built-in electrical field at the interface between CuInS2 NCs and electron/hole transport layers. This device architecture may provide a proper route toward simple and low-cost alternative designs for photodetectors.

Construction of Synergistic Co and Cu Diatomic Sites for Enhanced Higher Alcohol Synthesis

Construction of Synergistic Co and Cu Diatomic Sites for Enhanced Higher Alcohol Synthesis

Investigation of the Role of Copper Species-Modified Active Carbon by Low-Temperature Roasting on the Improvement of Arsine Adsorption.

Traditional adsorbents undershot the expectations for arsine (AsH3) removal under low-temperature operation conditions in the industry. In this study, the copper (Cu) precursor was used to modify activated carbon and yield novel adsorbents by low-temperature roasting for high-efficiency removal of AsH3. The best conditions were determined as impregnation with 2 mol/L Cu(NO3)2 adsorbent and roasting at 180 °C. At a reaction temperature of 40 °C and an oxygen content of 1%, the AsH3 removal efficiency reached over 90% and lasted for 40 h and the best capacity of 369.6 mg/g was obtained with the Cu/Ac adsorbent. The characterization results showed the decomposition of Cu(NO3)2 during the low-temperature roasting process to form surface functional groups. The formation of the important intermediate Cu2(NO3)(OH)3 in the decomposition of Cu(NO3)2 into CuO plays a role in the good regeneration performance of the Cu/Ac adsorbent using water washing and the gas regeneration method. The results of in situ diffuse reflectance infrared Fourier transform spectroscopy combined with X-ray photoelectron spectroscopy demonstrated that the interaction of trace oxygen with Lewis (L) acid sites increased chemisorbed oxygen by 17.34%, significantly promoting the spontaneity of AsH3 oxidation reaction. These results provide a friendly economic method with industrial processes practical for AsH3 removal.

Low-Temperature Sintering of l-Alanine-Functionalized Metallic Copper Particles Affording Conductive Films with Excellent Oxidative Stability.

Here, the alpha amino acid l-alanine is employed as both a capping and stabilizing agent in the aqueous synthesis of submicron-sized metallic copper particles under ambient atmospheric conditions. The reduction of the copper(II) precursor is achieved using l-ascorbic acid (vitamin C) as the reducing agent. The nature of the complex formed between l-alanine and the copper(II) precursor, pH of the medium, temperature, and the relative proportion of capping agent are found to play a significant role in determining the size, shape, and oxidative stability of the resulting particles. The adsorbed l-alanine is shown to act as a barrier imparting excellent thermal stability to capped copper particles, delaying the onset of temperature-induced aerial oxidation. The stability of the particles is complemented by highly favorable sintering conditions, rendering the formation of conductive copper films at significantly lower temperatures (T ≤ 120 °C) compared to alternative preparation methods. The resulting copper films are well-passivated by residual surface l-alanine molecules, promoting long-term stability without hindering the surface chemistry of the copper film as evidenced by the catalytic activity. Contrary to the popular belief that ligands with long carbon chains are best for providing stability, these findings demonstrate that very small ligands can provide highly effective stability to copper without significantly deteriorating its functionality while facilitating low-temperature sintering, which is a key requirement for emerging flexible electronic applications.

Hybrid Cu-Containing Compounds Based on Lacunary Strandberg Anions: Synthesis under Mild Conditions, Crystal Structure, and Magnetic Properties.

A one-pot reaction of a copper source (metallic powder Cu0 or Cu2+ salts) and bpy (bpy = 2,2'-bipyridine) in the presence of (NH4)2HPO4 and (NH4)6Mo7O24·4H2O yields heterometallic hybrid compounds of the general type {[Cu(bpy)n(H2O)m]p[P2MoxOy]}. The structures exhibit a number of phosphomolybdate POMs including not only a common Strandberg anion [P2Mo5O23]6- but also its unprecedented bi- and trilacunary derivatives [P2Mo3O18]8- and [P2Mo2O15]8-. The structural determinants including the metal source (copper powder vs copper salts), counterion of the salts, and stoichiometry of the reagents were examined. An ex situ EPR study revealed the formation of different CuII complexes in the reaction mixture depending on the copper precursor. The obtained compounds have been found to possess selectivity toward the sorption of methylene blue in a mixture of organic dyes. DC magnetic measurements of 1-3 indicate rather strong antiferromagnetic metal-metal exchange interactions. Compound 1 exhibits field-induced slow magnetic relaxation in AC magnetic measurements, which is a rarely observed phenomenon among Cu(II) complexes.

Directional Doping and Cocrystallizing an Open-Shell Ag39 Superatom via Precursor Engineering.

Metal precursors employed in the bottom-up synthesis of metal nanoclusters (NCs) are of great importance in directing their composition and geometrical structure. In this work, a silver nanocluster co-protected by phosphine and thiolate, namely, [Ag39(PFBT)24(TPP)8]2- (Ag39, PFBT = pentafluorobenzenethiol, TPP = triphenylphosphine), was isolated and structurally characterized. It adopts a three-layered Ag13@Ag18@Ag8S24P8 core-shell structure. The Ag13@Ag18 kernel is unusual in multilayer noble metal NCs. By introducing a copper precursor in the synthesis, a bimetallic nanocluster [Ag37Cu2(PFBT)24(TPP)8]2- (Ag37Cu2) with an identical structure to Ag39 apart from two outer Ag atoms being substituted by Cu atoms was obtained. Astoundingly, the Cu precursor used in the synthesis was found to be critical in determining the final structure. The alteration of the Cu precursor led to the cocrystallization of the above alloy nanocluster with a Ag14 nanocluster, namely, [Ag37Cu2(PFBT)24(TPP)8]2-·[Ag14(PFBT)6(TPP)8] (Ag37Cu2·Ag14). The electronic structure analyzed by theoretical calculation reveals that Ag39 is a 17-electron open-shell superatom. The optical absorption of Ag39, Ag37Cu2, and Ag37Cu2·Ag14 was compared and studied in detail. This work not only enriches the family of alloy metallic nanoclusters but also provides a metal NC-based cocrystal platform for in-depth study of its crystal growth and photophysical property.

Novel Fabrication of Silver-Coated Copper Nanowires with Organic Compound Solution.

Copper nanowires and Cu-Ag nanowires have various potential applications, such as transparent conductive film, flexible electronics, and conductive filler. In this study, we developed a new green fabrication method for silver-coated copper nanowires using methylsulfonylmethane (DMSO2), which is an environmentally friendly chemical at the food-grade level, to replace toxic chemicals, including ammonia, in the silver coating process. Copper nanowires were synthesized under various reaction temperatures and concentrations of hydrazine (N2H4), ethylenediamine (EDA), sodium hydroxide (NaOH), and copper precursor. The reaction temperature higher than 70 °C caused the oxidation of copper products and evaporation of the sample solution. The optimal conditions to synthesize copper nanowires more than 18 µm in length and 25–45 nm in diameter were determined: 9 M of NaOH, 50 µL of EDA, 17 mM of CuCl2, 5.7 mM of N2H4, and 70 °C reaction temperature. Cu-Ag nanowires, which have about a 12 nm thick silver shell, were successfully fabricated at room temperature under 1 mM of silver nitrate (AgNO3) and 1 wt % of DMSO2. Synthesis conditions for copper and silver-coated copper nanowires have been optimized.

Analysis of enargite thin films synthesized from carbon-containing and novel carbon-free processing methods

Current processing routes to produce thin films of emerging photovoltaic absorber Cu3AsS4 enargite use nanoparticle-based solution precursors that leave impurities in treated films. Spatial mapping of these carbonaceous impurities and analysis of their probable formation pathways reveal effective strategies toward avoiding secondary phase formation in these films. Leveraging these results, new fabrication pathways are introduced for thin enargite films based on evaporated copper precursor films. Unlike nanoparticle-based films, evaporated copper-based enargite films do not contain a carbonaceous residue, a Raman-active secondary phase, or a fine-grain layer. Enargite films produced from the conversion of evaporated copper films to copper sulfide are compared with nanoparticle-based films through current density-voltage analysis. Surprisingly, these films have similar photoconversion efficiencies which indicate the carbonaceous secondary phases are not responsible for current low-efficiency technology. A post-deposition diammonium sulfide solution etch is investigated to remove arsenic-based secondary phases and produces the highest short circuit currents, fill factors, and efficiencies to date for enargite-based photovoltaic technology. By introducing precursor films and processes that result in phase-pure enargite films, this work broadens the scope of synthesis pathways to enable more scalable processing methods that can inform effective strategies for the development of this emerging PV technology.

Evaluation of Zebrafish Toxicology and Biomedical Potential of Aeromonas hydrophila Mediated Copper Sulfide Nanoparticles.

The present study deals with extracellular synthesis and characterization of copper sulfide (CuS) nanoparticles using Aeromonas hydrophila, and the biological applications of the synthesized CuS like antibacterial, anti-inflammatory, and antioxidant activity were reported. Further, the toxicological effects of the CuS were evaluated using zebrafish as an animal model. The primary step of the synthesis was carried out by adding the precursor copper sulfates to the culture supernatant of Aeromonas hydrophila. The UV-visible spectrophotometer was used to characterize the synthesized nanoparticles, and the peak was obtained at 307 nm through the reduction process. Fourier transform infrared spectroscopy (FTIR) was involved to find out the functional groups (carboxylic acid, alcohols, alkanes, and nitro compounds) associated with copper sulfide nanoparticles (CuS-NPs). Atomic force microscopy (AFM) was used to characterize the CuS topographically, and a scanning electron microscope (SEM) revealed about 200 nm sized CuS nanoparticles with agglomerated structures. Overall, the characterized nanoparticles can be considered as a potential candidate with therapeutic proficiencies as antibacterial, antioxidant, and anti-inflammatory mediator/agents.

Enhanced photocatalytic and antifungal activity of ZnO–Cu2+and Ag@ZnO–Cu2+ materials

Zinc oxide is one of the most versatile nanostructured materials with a broad range of applications. Besides, its physicochemical properties can be tuned easily by synthesis conditions to be optimal for a specific application. In our group, we aim for the production of visible light-active materials with enhanced antimicrobial activity. Thus, we synthesize ZnO–Cu2+and Ag@ZnO–Cu2+ by using a fast and robust microwave solvothermal reaction. We investigate the limit of solubility of Cu2+into ZnO lattice producing Cu doped ZnO materials with different doping levels (1, 2, 3, 4, and 5 at. %, Cu/Zn). We also investigate the role of the copper precursor, using copper(II) acetate or copper(II) sulfate as model precursors. Copper acetate incorporates more efficiently into ZnO lattice by decreasing the Eg value of the doped materials at low doping levels. Furthermore, we study the composites Ag@ZnO–Cu2+ aiming to reduce doping levels and to improve antimicrobial activity. Characterization of the materials by different techniques demonstrates their uniform size, purity, crystallinity, and visible light activity. In this study, we evaluate airborne fungal contamination and demonstrate the capacity of ZnO–Cu2+ and Ag@ZnO–Cu2+ to inhibit fungal growth. We studied the microbiological quality of indoor air (vivarium) by sampling air under different conditions. By sampling air with a photocatalytic prototype, the amount of fungi in the air decreases considerably, particularly fungi that can enter the lung. In addition, ZnO–Cu2+ shows excellent antifungal activity against Candida sp at low doses. We use Atomic force microscopy (AFM) and holotomographic microscopy (HTM) to provide further evidence on the capacity of the prepared materials to achieve effective damage to fungal cells and to inhibit biofilm formation.

Rapid Synthesis of Metal Nanoparticles Using Low-Temperature, Low-Pressure Argon Plasma Chemistry and Self-Assembly.

The synthesis of metal nanoparticles has become a priority for the advancement of nanotechnology. In attempts to create these nanoparticles, several different methods: chemistry, physics, and biology, have all been used. In this study, we report the reduction of cations using argon plasma chemistry to produce nanoparticles of gold (AuNPs), silver (AgNPs), and copper (CuNPs). Although other groups have used plasma-reduction methods to synthesize metal nanoparticles from their cation counterparts, these approaches often require plasma|liquid state interactions, high temperature, specific combinations of gases, and extended treatment times (>10 minutes), for which only specific cations (noble or non-noble) may be reduced. As a result, we have developed a non-thermal, low-pressure argon-plasma|solid state approach for the reduction of both noble and non-noble cations. More specifically, when 50-μL droplets of 2-mM solutions of gold(III) chloride, silver nitrate, or copper(II) sulfate are exposed to vacuum, they undergo an evaporation process. As the pressure in the chamber decreases to 220 mtorr, the droplets become completely evaporated, leaving behind a metal precursor. Nucleation and growth studies reveal that when the metal precursors of gold(III) chloride, silver nitrate, and copper(II) sulfate are treated with 80 watts of argon plasma for 5, 60, and 150 seconds, respectively, nanoparticles could be synthesized with efficiency rates of upwards of 98%. The size of nanoparticles synthesized in this work was studied using Scanning Electron Microscopy, and the scattering properties of the nanoparticles was studied using UV/Vis spectroscopy. Transmission Electron Microscopy with corresponding elemental analysis was also very useful in confirming the identity of the synthesized nanoparticles. The results from this study reveal that we have synthesized metal nanoparticles with distinct chemical and physical properties. Scanning Electron Microscopy depicts AgNPs with a round-shape and diameters from 40 - 80 nm, while AuNPs were hexagonal, with sizes from 40 - 80 nm, and CuNPs were rod-shaped, with dimensions 40 by 160 nm. Our findings demonstrate that the argon plasma approach used in this study is a rapid, green, and versatile reduction method for the synthesis of both noble and non-noble metal nanoparticles.

Recovery of Cathode Copper and Ternary Precursors from Cus Slag Derived by Waste Lithium-Ion Batteries: Process Analysis and Evaluation

Recovery of Cathode Copper and Ternary Precursors from Cus Slag Derived by Waste Lithium-Ion Batteries: Process Analysis and Evaluation

Biogenic Synthesis of Cu-Doped ZnO Photocatalyst for the Removal of Organic Dye.

The Cu-doped ZnO photocatalysts were prepared with a green and coprecipitation approach by using water hyacinth (Eichhornia crassipes) aquatic plant extract. In the preparation process, different amount of copper precursors such as 1, 2, 3, 4, and 5% of molar ratio were added to zinc nitrate precursors and abbreviated as Cu-ZnO (1%), Cu-ZnO (2%), Cu-ZnO (3%), Cu-ZnO (4%), and Cu-ZnO (5%), respectively. The characterization of the obtained samples was carried out, and the removal of the methylene blue (MB) dye was examined. Out of all catalysts, Cu-ZnO (3%) had the best photocatalytic performance and 89% of the MB dye was degraded. However, the degradation performances of blank (without catalysts), ZnO, Cu-ZnO (1%), Cu-ZnO (2%), Cu-ZnO (4%), and Cu-ZnO (5%) catalysts were 6, 54, 69, 83, 80, and 73%, respectively. Therefore, the use of water hyacinth plant extract with the optimum amount of Cu added to ZnO during the preparation of the catalyst could have a promising application in the degradation of organic pollutants.

Nano Cu2O catalyzed ultrasonic-assisted green synthesis of some seleno[2,3-b] quinoline derivatives

In this report, copper (I) oxide (Cu2O) nanocatalyst was synthesized by chemically reducing a copper precursor with ascorbic acid (AA) and trisodium citrate (TSC) in alkali medium. The influence of Cu2O NPs on the developmental production of selenoquinoline derivatives (5a-c) under room temperature, thermal (80 °C), and different sonication conditions (power, irradiation time, catalyst loading, and other copper salts) was examined. The results indicated that increasing the ultrasonic power (300 W) for short time (60 min), the yield of seleno[2,3-b] quinoline derivatives (5a-c) improved to more than 95%. A proposed mechanism of this approach has been explained. Furthermore, the catalytic system can be recycled without affecting yields or reaction rates significantly. The main features of this protocol are the use of mild reaction conditions, no production of side products, easy work-up, and high yields.

Genesis and Properties of MOx/CNTs (M = Ce, Cu, Mo) Catalysts for Aerobic Oxidative Desulfurization of a Model Diesel Fuel

Aerobic oxidative desulfurization of a model diesel fuel over MOx/CNTs catalysts (M = Ce, Cu, Mo) was studied to develop innovative technology for cleaning motor fuels to EURO-5 standard. It was shown that the thermal stability of catalysts improves in the following order of metal Сu < Сe < Мо. The disordering of the carbon matrix of support increases in the next row of M: Mo < Ce < Cu, which is accompanied by an increase in the specific surface area of the samples (40 → 105 m2/g). The forms of stabilization of the active component (CeO2, CuO/Cu2O/ Cu, or MoO3/MoO2) were revealed, indicating a partial reduction of the metal cations during the thermal decomposition of copper and molybdenum precursor compounds deposited on CNTs. In oxidative desulfurization of a model diesel fuel over MOx/CNTs catalysts at 150 °C the total conversion of dibenzothiophene increased in the next row of M: Се < Сu < Мо. It was found that at 150 °C over the optimum MoOx/CNTs catalyst the highest dibenzothiophene conversion 95–99% is observed. It was assumed that the high activity of MoOx/CNTs is associated with both the oxidizing ability and the tendency of MoOx to chemosorption of sulfur compounds.