Copper Oxide Nanosheets Research Articles

Boosting Electrochemical Nitrate Reduction to Ammonia by Fe Doped CuO/Co3O4 Nanosheet/Nanowire Heterostructures.

The electrochemical nitrate reduction reaction (NO3-RR) is a novel green method for ammonia synthesis. The development of outstanding NO3-RR performance is based on reasonable catalyst. Metal oxides have garnered significant attention due to their exceptional electrical conductivity and catalytic properties. Doping serves as an effective strategy for enhancing catalyst performance due to its ability to change the electron cloud distribution and energy levels. In this study, we develop a heterojunction catalyst Fe doped copper oxide nanosheet and cobalt tetroxide nanowire growing on carbon cloth simultaneously (Fe-CuO@Co3O4/CC) via hydrothermal method. The well-designed Fe-CuO@Co3O4/CC has excellent NH3 yield (470.9 μmol h-1 cm-2) and Faraday efficiency (FE: 84.4%) at -1.2 V versus reversible hydrogen electrode (vs. RHE). The heterostructure increases the specific surface area of the catalyst, and the possibility of contact between the catalyst and NO3- ions, enhances the catalytic efficiency. In addition, the catalyst has excellent stability and can stably carry out the electrocatalytic nitrate reduction reaction (NO3-RR), which provides a way for further research on the high-efficiency reduction of nitrate.

Enhanced synergistic antiviral effects of thermally expanded graphite and copper oxide nanosheets in the form of a novel nanocomposite against herpes simplex virus type 1

Herpes simplex virus type 1 (HSV-1) is responsible for a wide range of human infections, including skin and mucosal ulcers, encephalitis, and keratitis. The gold standard for treating HSV-1 infections is acyclovir. However, the use of this drug is associated with several limitations such as toxic reactions and the development of drug-resistant strains. So, there is an urgent need to discover and develop novel and effective agents against this virus. For the first time, this study aimed to investigate the antiviral effects of the Thermally Expanded Graphite (TEG)-copper oxide (CuO) nanocomposite against HSV-1 and compare results with its constituent components. After microwave (MW)-assisted synthesis of TEG and CuO nanosheets as well as MW-CuO/TEG nanocomposite and characterization of all these nanomaterials, an MTT assay was used to determine their cytotoxicity. The quantitative real-time PCR was then used to investigate the effects of these nanomaterials on viral load. Three-hour incubation of HSV-1 with TEG nanosheets (500 μg/mL), MW-CuO nanosheets (15 μg/mL), and MW-CuO/TEG nanocomposite (35 μg/mL) resulted in a decrease in viral load with an inhibition rate of 31.4 %, 49.2 %, and 74.4 %, respectively. The results from the post-treatment assay also showed that TEG nanosheets (600 μg/mL), MW-CuO nanosheets (15 μg/mL), and MW-CuO/TEG nanocomposite (10 μg/mL) led to a remarkable decrease in viral load with an inhibition rate of 56.9 %, 63 %, and 99.9 %, respectively. The combination of TEG and MW-CuO nanosheets together and the formation of a nanocomposite structure display strong synergy in their ability to inhibit HSV-1 infection. MW-CuO/TEG nanocomposites can be considered a suitable candidate for the treatment of HSV-1 infection.

Multibiofunctional Self-healing Adhesive Injectable Nanocomposite Polysaccharide Hydrogel.

Injectable hydrogels with good antimicrobial and antioxidant properties, self-healing characteristics, suitable mechanical properties, and therapeutic effects have great practical significance for developing treatments for pressing healthcare challenges. Herein, we have designed a novel, self-healing injectable hydrogel composite incorporating cross-linked biofunctional nanomaterials by mixing alginate aldehyde (Ox-Alg), quaternized chitosan (QCS), adipic acid dihydrazide (ADH), and copper oxide nanosheets surface functionalized with folic acid as the bioligand (F-CuO). Gelation was achieved under physiological conditions via the dynamic Schiff base cross-linking mechanism. The developed nanocomposite injectable hydrogel demonstrated the fast self-healing ability essential to bear deformation and outstanding antibacterial properties along with ROS scavenging ability. Furthermore, the optimized formulation of our F-CuO-embedded injectable hydrogel exhibited excellent cytocompatibility, blood compatibility, and in vitro wound healing performance. Taken together, the F-CuO nanosheet cross-linked injectable hydrogel composite presented herein offers a promising candidate biomaterial with multifunctional properties to develop solutions for addressing clinical challenges.

Nanostructured assessment of copper oxide for latent fingerprint recognition

Nanotechnology has revolutionized the different fields of forensic science, particularly in the efficient examination of evidence. In this study, we report scalable synthesis of copper oxide (CuO) nanosheets by using hydrothermal method and its exploration in the forensic examination of latent fingerprints. The identification and structural characterization of CuO nanoparticles were carried out using advanced spectroscopic methods such as powder X-ray diffraction (PXRD), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The stabilization of CuO nanosheets in monoclinic symmetry (space group C2/c) was confirmed through Le Bail refinements. Morphological studies based on scanning electron microscopy (SEM) revealed that the CuO nanosheets exhibit, a rectangular, thin plate like morphology.The applicability of these nanosheets was tested for examining and developing fresh and aged (7 days old) latent fingerprints on dry, non-absorbent substrates using the powder dusting method. The formulation successfully developed sharp and clear fingerprints on various substrates, allowing the second-level details of the fingerprints to be viewed without any background interference. Additionally, these nanosheets are non-hazardous and cost-effective, making them a suitable fingerprint developing agent for a wide range of dry, non-absorbent surfaces recovered from crime scenes.

Copper oxide nanosheets as an effective nanozyme with haloperoxidase-like activity for the colorimetric detection of H2O2 and glucose

Copper oxide nanosheets (CuO NSs) have been successfully obtained by exploiting an effective one-step approach of sugar-blowing method followed by calcination. The nanosheets were characterized by several techniques like X-ray powder diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Impressively, CuO NSs display haloperoxidase (HPO) like catalytic activity which catalyses the oxidation of chloride ions by H2O2 giving rise to reactive chlorine species (RCS). A sensitive and selective colorimetric sensor was then demonstrated via the oxidation of chromogenic substrate 3,3′,5,5′- tetramethylbenzidine (TMB) by the novel nanoenzyme CuO NSs through the generation of RCS for H2O2 and glucose detection with limit of detection of 109 nM and 21 nM in the linear ranges of 4.6 µM to 769 µM and 0.22 µM to 19.57 µM respectively. Additionally, the methodology is validated for the analysis of glucose in real samples.

Zinc oxide nanoflakes supported copper oxide nanosheets as a bifunctional electrocatalyst for OER and HER in an alkaline medium

Bifunctional electrocatalysts are the attractive research in the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in the overall water-splitting reactions. The design and development of the cost-effective OER/HER bifunctional electrocatalysts with superior catalytic activity are still remaining as the big challenges. Herein, we have developed the CuO–ZnO nanocomposite as a bifunctional OER/HER electrocatalyst via simple chemical precipitation method. The nanocomposite was investigated for its crystalline structure, surface morphology and the functions of elements using XRD, FT-IR, SEM, TEM and XPS characterization techniques, respectively. The nanocomposite exhibited the excellent activity for the overall water-splitting in an alkaline medium. The CuO–ZnO nanocomposite showed the less onset potential of 1.4 and 0.15 V versus RHE in 1M KOH (Tafel slopes value of 0.180 and 0.400 V dec−1) for OER and HER, respectively. Hence, the as-prepared bifunctional electrocatalyst displayed the high stability for 10 h in the water electrolysis processes.

Biogenic synthesis of copper oxide nanosheets using Celastrus paniculatus: Insights into antibacterial and anticancer efficacy supported by computational study

The metallic nanomaterials synthesized using green nanotechnology have recently gained attention for their low-cost, simple preparation methods, and environmental sustainability. In this study, biogenic copper oxide nanosheets (CuO NS) were synthesized using the seed extract of Celastrus paniculatus, and characterized by various advanced instrumentation techniques including FTIR, XRD, FESEM, and TEM analysis. Docking simulation studies demonstrated that the interaction between CuO NS and the Staphylococcus aureus receptor (2I80) was strong, with docking scores ranging from −4.0 to −5.1 and a free binding energy of −24.48 ± 0.63 kcal/mol. The antibacterial activity of CuO NS against Staphylococcus aureus and Enterobacter aerogenes was analyzed by well diffusion method. In addition to that, antibiofilm, ROS generation, growth kinetics, and anticancer efficacy of CuO NS was also evaluated. The anticancer results indicated that CuO NS effectively reduced the cell viability of both cancer cell lines (MCF 7 & MDA MB 231). The findings from the antibacterial and anticancer studies suggest that the biologically synthesized CuO NS could serve as a promising alternative for bacterial diseases and cancer treatments.

Enhanced photocatalytic degradation of organic pollutants in water using copper oxide (CuO) nanosheets for environmental application

Rapid, inexpensive, and low-power/solar light-driven photocatalytic degradation of organic pollutants to deal with annually produced trillion tons of synthetic dye wastewater to prevent water scarcity issues, ecotoxicological risks, and human health has always been challenging. To overcome this limitation, the present study synthesized earth-abundant, inexpensive copper oxide nanosheets using a simple single-step hydrothermal route. The structural, physicochemical, and functional properties of the nanosheets have been characterized using several characterization techniques. The photocatalytic activity was studied for two commonly industrially used organic dyes, Methylene Blue (MB) and Rhodamine B (RhB). The importance of this work is the usage of a cheap commercially available Phillips UV light (11 W) as well as direct sunlight. With several optimized conditions, almost complete degradation of both dyes was achieved within 35 minutes under low-power UV light and within 70 minutes by the direct illumination of natural sunlight. The enhanced photocatalytic performance can be correlated to the synergetic effect of a higher charge transfer mechanism, good catalytic ‘active surface area’ availability (13.2 m2/g), and several optimized parameters that affect the reaction efficacy. Additionally, five repeated uses of nanosheets without sacrificing performance confirmed their stability and sustainability as a promising candidate for large-scale industrial textile wastewater remedies.

Design and synthesis of magnesium-modified copper oxide nanosheets as efficient electrocatalysts for CO2 reduction.

Electroreduction of carbon dioxide (CO2) to multiple carbon products plays a significant role in carbon neutrality and the production of valuable chemicals. Herein, we developed a magnesium-modified copper oxide nanosheet catalyst (Mg-CuO) using a post-impregnation method. Comprehensive elemental analysis demonstrated the effective incorporation of magnesium into CuO nanosheets, resulting in a noticeable alteration of the electron density of Cu atoms. Consequently, the Mg-CuO nanosheets exhibited an increased efficiency for CO2 electroreduction in comparison with the unmodified CuO nanosheets. The optimized Mg-CuO catalyst exhibited faradaic efficiencies of 46.33% for ethylene production and 62.64% for C2+ production at -1.3 V vs. reversible hydrogen electrode (RHE). DFT proved that the introduction of Mg species could increase the charge density of Cu and decrease the adsorption energy of *CO, which promoted C-C coupling and enhanced the selectivity of C2+ products. This study presents an effective way to adjust the electronic structure of common copper-based electrocatalysts and the corresponding interaction with *CO, resulting in an improved faradaic efficiency of C2+ products.

Nonlinear optical properties in chiral copper oxide nanosheets.

Chiral transition metal oxides (TMOs) are in the forefront of research as potential active materials in various optoelectronic applications. However, the nonlinear optical (NLO) properties of the chiral TMOs have not been fully understood. Here, several kinds of copper oxide nanosheets capped with different chiral amino acids are synthesized. Notably, we investigate the NLO activities of these materials, including broadband second harmonic generation and transformation of nonlinear optical properties from saturable absorption to reverse saturable absorption. This work will broaden the use of chiral TMO materials in nonlinear photonic devices.

Catalytic mechanism of the Schikorr reaction promoted by the copper oxide nanosheet during a low-temperature hydrothermal process

The Schikorr reaction 3Fe(OH)2 → Fe3O4 + H2 + 2H2O, has been proposed for nearly 100 years. Although it has shown great potential application value in steel corrosion, recovery of ferrous waste liquid, and other fields, the reaction catalyst itself is still unclear. We confirmed that Cu(II) ions were essentially converted into the oriented CuO nanosheets as a catalyst during a low-temperature hydrothermal process. Moreover, this catalytic reaction required the participation of hydroxide ions without relationship to sulfate ions and trace dissolved oxygen molecules in the solution. The growth process tracing experiment found that green rust was the reaction intermediate, and the reaction stage from green rust to Fe3O4 was the reaction rate control stage. Finally, the reaction rate was clearly defined by using the FWHM of the XRD diffraction peak of the (3,1,1) crystal plane of Fe3O4, and the activation energy was calculated as 79.46 ± 5.05 kJ mol−1.

Single-Site SnOCu Pairs with Interfacial Electron Transfer Effect for Enhanced Electrochemical Catalysis and Sensing.

As advanced electrochemical catalysts, single-atom catalysts have made great progress in the field of catalysis and sensing due to their high atomic utilization efficiency and excellent catalytic performance. Herein, stannum-doped copper oxide (CuOSn1 ) nanosheets with single-site SnOCu pairs as active sites are synthesized as electrocatalysts for biological molecule detection. Compared with CuO-based electrochemical sensors, the CuOSn1 -based electrochemical sensors have improved detection sensitivity with a rapid electrochemical response. Theoretical calculation reveals that the single-site SnOCu pairs induced interfacial electronic transfer effect can strengthen hydroxy adsorption and thus reduce the energy barrier of the biological molecule oxidation process. As a concept application, electrochemical detection of dopamine and uric acid molecules is achieved, exhibiting satisfactory sensitivity and selectivity. This work demonstrates the advantages of single-site SnOCu pairs in electrochemical catalysis and sensing, which provides theoretical guidance for understanding the structure-activity relationship for sensitive electrochemical sensing.

Self-supported porous copper oxide nanosheet arrays for efficient and selective electrochemical conversion of nitrate ions to nitrogen gas

• Porous copper oxide nanosheets grow in situ on nickel foam surface (NF). • Removes low-concentration nitrate rapidly with almost no production. • CuO/NF exhibits excellent stability and N 2 selectivity in nitrate reduction. Electrochemical techniques have shown advantages for the removal of low-concentration nitrate. Here, copper oxide nanosheets were grown on self-supporting nickel foam (NF) to prepare electrodes (CuO/NF), which realized the rapid and highly selective conversion of nitrate pollutants in sewage into non-toxic and harmless N 2 . The CuO/NF afforded 100% NO 3 – removal within 100 min and 99.53% selectivity for N 2 at –50 mA without producing a lot of by-products (NO 2 – , NH 4 + , and N 2 H 4 ). Furthermore, 81.8% of NO 3 – was removed under the given conditions after six experimental repetitions. These results suggest that the catalyst has excellent electrochemical stability. The performance of CuO/NF for the electrocatalytic removal of NO 3 – in simulated wastewater (which contained Cl – and SO 4 2– ) was almost unaffected. Because of the high efficiency, high stability, and low cost of CuO/NF, this catalyst is practical for the removal of nitrate for wastewater purification. Copper oxide nanosheets grown on nickel foam realizes rapid, selective and efficient conversion of nitrate in water.

Hydrazine High-Performance Oxidation and Sensing Using a Copper Oxide Nanosheet Electrocatalyst Prepared via a Foam-Surfactant Dual Template.

This work demonstrates hydrazine electro-oxidation and sensing using an ultrathin copper oxide nanosheet (CuO-NS) architecture prepared via a versatile foam-surfactant dual template (FSDT) approach. CuO-NS was synthesised by chemical deposition of the hexagonal surfactant Brij®58 liquid crystal template containing dissolved copper ions using hydrogen foam that was concurrently generated by a sodium borohydride reducing agent. The physical characterisations of the CuO-NS showed the formation of a two-dimensional (2D) ultrathin nanosheet architecture of crystalline CuO with a specific surface area of ~39 m2/g. The electrochemical CuO-NS oxidation and sensing performance for hydrazine oxidation revealed that the CuO nanosheets had a superior oxidation performance compared with bare-CuO, and the reported state-of-the-art catalysts had a high hydrazine sensitivity of 1.47 mA/cm2 mM, a low detection limit of 15 μM (S/N = 3), and a linear concentration range of up to 45 mM. Moreover, CuO-NS shows considerable potential for the practical use of hydrazine detection in tap and bottled water samples with a good recovery achieved. Furthermore, the foam-surfactant dual template (FSDT) one-pot synthesis approach could be used to produce a wide range of nanomaterials with various compositions and nanoarchitectures at ambient conditions for boosting the electrochemical catalytic reactions.

Highly Selective Electrochemical CO2 Reduction to C2 Products on a g-C3N4-Supported Copper-Based Catalyst.

Herein, a novel approach used to enhance the conversion of electrochemical CO2 reduction (CO2R), as well as the capacity to produce C2 products, is reported. A copper oxide catalyst supported by graphite phase carbon nitride (CuO/g-C3N4) was prepared using a one-step hydrothermal method and exhibited a better performance than pure copper oxide nanosheets (CuO NSs) and spherical copper oxide particles (CuO SPs). The Faradaic efficiency reached 64.7% for all the C2 products, specifically 37.0% for C2H4, with a good durability at -1.0 V vs. RHE. The results suggest that the interaction between CuO and the two-dimensional g-C3N4 planes promoted CO2 adsorption, its activation and C-C coupling. This work offers a practical method that can be used to enhance the activity of electrochemical CO2R and the selectivity of C2 products through synergistic effects.

Preparation of copper oxide nanosheets by pulsed laser ablation in liquid for anticancer, antioxidant, and antibacterial activities

In this work, the preparation of copper oxide (CuO) nanosheets by laser ablation in water was demonstrated. The optical, structural, stability, and morphological properties of CuO nanosheets were investigated using UV–Vis spectrophotometer, X-ray diffraction (XRD), scanning electron microscope (SEM), and zeta potential (ZP). The XRD results confirm the formation of crystalline (CuO) with a monoclinic phase. The optical energy gap of CuO nanosheets was found to be 2.2 eV at 300 k. The average thickness of the synthesized copper oxide nanosheets is 25 nm. Energy dispersive X-ray result confirms the formation of stoichiometric CuO. The zeta potential result confirms the synthesized CuO colloid is stable. Gram-positive bacteria are found to be more susceptible to CuO nanosheets than Gram-negative bacteria. The synthesized copper oxidenanosheets are tested for antibacterial activity against Gram (+ve) and Gram (-ve) bacteria stains. The results suggest that CuO NPS can give hydrogen atoms and remove the unstable electron from DPPH at a rate of 200 μg/ml than 12.50 μg/ml. The results demonstrate that the copper oxide nanosheets have an effective antioxidant. Furthermore, according to a cytotoxicity assay, when cancer cells are incubated with copper oxide nanosheets, they are unable to grow well. copper oxide nanosheets can induce apoptosis and suppress pancreatic cell proliferation.

In situ grown oxygen-vacancy-rich copper oxide nanosheets on a copper foam electrode afford the selective oxidation of alcohols to value-added chemicals

Selective oxidation of low-molecular-weight aliphatic alcohols like methanol and ethanol into carboxylates in acid/base hybrid electrolytic cells offers reduced process operating costs for the generation of fuels and value-added chemicals, which is environmentally and economically more desirable than their full oxidation to CO2. Herein, we report the in-situ fabrication of oxygen-vacancies-rich CuO nanosheets on a copper foam (CF) via a simple ultrasonication-assisted acid-etching method. The CuO/CF monolith electrode enables efficient and selective electrooxidation of ethanol and methanol into value-added acetate and formate with ~100% selectivity. First principles calculations reveal that oxygen vacancies in CuO nanosheets efficiently regulate the surface chemistry and electronic structure, provide abundant active sites, and enhance charge transfer that facilitates the adsorption of reactant molecules on the catalyst surface. The as-prepared CuO/CF monolith electrode shows excellent stability for alcohol oxidation at current densities >200 mA·cm2 for 24 h. Moreover, the abundant oxygen vacancies significantly enhance the intrinsic indicators of the catalyst in terms of specific activity and outstanding turnover frequencies of 5.8k s−1 and 6k s−1 for acetate and formate normalized by their respective faradaic efficiencies at an applied potential of 1.82 V vs. RHE.

A new combustion method for the synthesis of copper oxide nano sheet and Fe3O4/CuO magnetic nanocomposite and its application in removal of diazinon pesticide

Pesticides used in agriculture and their entry into water is one of the most important environmental problems in the world. In recent years, much attention has been paid to the removal of pesticides, such as diazinon, by researchers. The subject of this research is the remove of diazinon from water using a CuO nanosheet and Fe3O4/CuO nanocomposite, synthesized by a new combustion method. The effect of some factors such as contact time, pH, temperature, the amount of adsorbent, concentration of diazinon and presence of electrolyte has been investigated. Isotherm, kinetics and thermodynamics of absorption in the optimal conditions were investigated. Another goal of this study is to use a fast and cost-effective method for the synthesis of CuO nanosheet and Fe3O4/CuO nanocomposite. After synthesis, were characterized by methods such as FTIR, XRD, FE-SEM, VSM, EDX and element distribution. The results showed that the Fe3O4/CuO nanocomposite is better than CuO nanosheet for this purpose. In optimal conditions, pH = 7, absorbent concentrations of 0.035 mg/ml with a diazinon concentration of 2 mg/L and contact time of 10 min removal percent of this pesticide was 94%. The standard deviation percentage of the method for the real sample, with four repetitions, was equal to 3.8%. The recovery for three repetitions was 97.6% in the range of the real sample. Langmuir isotherm and second-order kinetics were investigated to explain the absorption mechanism. Thermodynamic investigations have shown that the absorption is a spontaneous process at low temperatures (ΔH<0, ΔG>0).

Gold Nanoparticles Decorated Copper Oxide Nanosheets Sensor for Hydrogen Sulfide Gas Sensing at Room Temperature

This study exhibits a highly H2S-selective gas sensor based on copper oxide nanosheets (CuO-NSs) material. CuO-NSs are fabricated by a simple and economical method. CuO-NSs are decorated by gold nanoparticles (AuNPs) and used to detect H2S at room temperature. The AuNPs decorated CuO sensor has responses of 36.55% to 69.67% at 0.1 to 0.5 ppm of H2S while the pure sensor has responses from 4.77% to 13.37%. It can be seen that AuNPs can enhance H2S sensing responses five to nine times higher than pure one. The sensor also shows high H2S selectivity against NH3, SO2 and volatile organic compounds (VOCs). The beneficial effect of AuNPs allow the H2S detection of CuO material down to ppb and even lower level, which make it possible to be applied in environmental applications and portable devices.

Preparation and Antibacterial Activity of Nano Copper Oxide- Loaded Zeolite 10X.

Copper oxide nanosheet-loaded zeolite 10X nanocomposites (CuO-zeolite NCs) were successfully prepared by modifying zeolite 10X with CuSO4 aqueous solution. The formation of copper oxide nanosheets on the surface of zeolite 10X was observed by SEM. The thickness of CuO nanosheets was about 30–40 nm, and the width ranged from 200 nm to 300 nm. The XRD patterns showed that the new diffraction peaks of copper oxide appeared at 35.6° and 38.8°. According to the XPS results, the Cu 2p3/2 and Cu 2p1/2 peaks in CuO-zeolite NC were centered at 934.1 eV and 953.8 eV, which could be attributed to Cu(II). The EDS analysis revealed that the energy spectra of calcium gradually decreased as the copper ion concentration increased during the preparation of CuO-zeolite NCs. Meanwhile, the energy spectra of copper increased gradually, and the highest content of copper in CuO-zeolite NCs reached 22.35 wt.%. The BET surface areas of zeolite 10X and CuO-zeolite NCs were 587 and 363 m2/g, respectively, based on the N2 adsorption–desorption experiment. The antibacterial activities of CuO-zeolite NC were evaluated using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The antibacterial activities were related to both copper ion content in CuO-zeolite NCs and the particle size of copper oxide. The results showed that nano CuO-loaded zeolite 10X inhibited the activity of E. coli and S. aureus. CuO-zeolite NCs are expected to be further used in antifouling coating.