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The detection of Hydrogen sulfide (H2S) gas at room temperature measurement has gained interest owing to its low-power consumption, high stability and reducing the risk of explosion within the sight of flammable gases. In this study, we present a novel low-cost and environmental-friendly approach in developing SnO2 and CuO nanoparticles (green approach) and their deployment in transistor (bi-layer approach) for the detection of hydrogen sulfide (H2S) vapors. The crystallite size of as-synthesized SnO2 and CuO NPs were revealed with aid of diffraction peaks which were found to be 14 nm and 19 nm respectively and the elemental composition with structural morphology (spherical) were determined by EDAX and Fe-SEM analysis respectively. The CuO nanoparticles interaction with the surface of SnO2 affirms a p-n junction formation with large electron-hole movements, while the interaction of H2S gas molecules on to the surface of CuO leads to the formation of CuS which awfully reduces electrical resistance enhancing the electrical conductivity and the sensor response. The high sensitivity of 1.86 μA/ppm and selectivity response of 89.46 % was achieved for the exposure of H2S analyte among other analytes exposed such as NO2, CO, C2H5OH and C3H8. The results demonstrate that sensor designed is potent for the use in industrial, environmental, and safety applications, contributing to the mitigation of H2S-related risks.

This research highlights the significant role of green synthesis in the production of copper oxide (CuO) nanoparticles by using natural extracts as reducing agents. These nanoparticles have shown promising potential in two key applications: photocatalytic degradation of industrial dye effluents and electrochemical sensing of ciprofloxacin. The study found that Arundinaria gigantea leaf extract is an effective reducing agent for synthesizing well-defined crystalline structure CuO nanoparticles, with an average size of 36 nm. The CuO nanoparticles have demonstrated high efficiency in photocatalytic applications, effectively degrading AR88 dye under UV irradiation, making them a viable solution for eco-friendly water purification. Additionally, when incorporated into an electrochemical sensor, these CuO nanoparticles have improved sensitivity and selectivity in detecting ciprofloxacin in aqueous solutions with high accuracy and precision. This study emphasizes the versatility and effectiveness of green-synthesized CuO nanoparticles for various practical uses.

The quest for a low-cost, flexible thermoelectric generator using eco-friendly metal oxide-based materials for low-temperature applications has motivated this work. The work compares the performance of amine-functionalized multi-walled carbon nanotubes (MWCNT-NH 2) and metal oxide nanoparticles (CuO, NiO, and Fe 2 O 3) ink-based hybrid flexible thermoelectric generators. Study reveals that the thermoelectric performance of a flexible thermoelectric generator improves by fine-tuning the materials crystallite size, bandgap, carrier concentration, carrier mobility, resistivity, the Seebeck coefficient, and micro-porosity of the ink film, which could be materialized by using hybrid thermoelectric materials. Among the three fabricated devices, MWCNT-NH 2 /NiO hybrid flexible thermoelectric generator exhibits a maximum power output of 1.44 nW at ΔT= 100 °C. The maximum power density displayed by MWCNT-NH 2 /NiO hybrid device is 59.3 nW/cm2 at ΔT= 100 °C, which is 23.28% and 332.8% higher than that of MWCNT-NH 2 /CuO and MWCNT-NH 2 /Fe 2 O 3 -based devices, respectively. The performance of MWCNT-NH 2 /NiO is comparatively superior to some previously reported works. [ABSTRACT FROM AUTHOR]

Thin films consisting of quadrilateral nanoplates of CuO on the surface of a Cu plate were successfully synthesized in a two-dimensional microspace by the hydrothermal oxidation of a Cu plate using aqueous (NH4)2S2O8 solution as the oxidizer. Selective crystal growth was clearly observed in the two-dimensional microspace formed between the Al2O3 and the Cu plates, and a highly crystalline CuO quadrilateral nanoplate thin film was formed on the surface of the Cu plate that faced the Al2O3 plate. Similar experiments were performed by replacing the Al2O3 plate with Cu, Ti, or SUS316L plates as the substrate, to investigate the effect of the substrate facing the Cu plate. Using different substrates resulted in significant differences in the morphology of the CuO thin film on the Cu plate facing the substrate. The present study demonstrates that the use of a two-dimensional microspace can be extremely effective in controlling the nanostructure of thin films. [ABSTRACT FROM AUTHOR]

Assembling transition-metal oxides (TMOs) and MXene with strong interfacial interactions is an effective method to overcome the drawbacks of TMOs as anodes for lithium-ion batteries (LIBs) such as large volume expansion and low conductivity. Herein, a CuO nanorod/MXene heterojunction (denoted as CuO/MXene) with a synergistic effect was constructed with a "sheet-rod-pore" hierarchical nanostructure by electrostatic self-assembly. Specifically, encapsulated CuO nanorods exert superiority in the high reversible capacity and increase the interlayer distance of the MXene matrix to explore more storage spaces. MXene could significantly boost the conductivity, accommodate volume variation, and inhibit structure collapse as a buffer network. Density functional theory (DFT) calculations confirm the strong electron transport and lithium affinity at the CuO/MXene heterointerface, elucidating the reasons for the enhanced lithium storage capacity (436.4 mAh g–1 at 500 mA g–1), ion diffusion kinetics, and structural stability after cycling than pure CuO and MXene. When paired with the LiCoO2 cathode, the full cell delivers good cycling stability after 140 cycles, indicating the practical applicability of CuO/MXene. This work not only validates the robust interfacial interaction of TMO/MXene heterojunction but also explores an effective strategy to prepare promising anode materials for the next-generation LIBs. [ABSTRACT FROM AUTHOR]

3D electrode design is proposed as an attractive approach to simultaneously increasing energy and power densities for all-solid-state thin film lithium microbatteries (TFBs). However, currently reported TFBs based on 3D electrodes prepared by atomic layer deposition or physical vapor deposition suffer from relatively low areal capacity and high fabrication cost. In this work, a 3D CuO nanowire array electrode with controllable thickness is directly prepared on a conductive substrate by a facile wet chemistry route, based on which a high-performance CuO/LiPON/Li TFB is efficiently constructed. Possessing abundant electrode/electrolyte interface contact, shortened ion diffusion length, and accommodation capability for volume change, the CuO/LiPON/Li TFB exhibits a large areal capacity (92 μAh cm−2 at 15 μA cm−2), high rate capability (11 μAh cm−2 at 960 μA cm−2), and good cycle performance (nearly no capacity loss after 70 cycles). This work establishes the great potential of preparing 3D electrodes by wet chemistry routes for realizing high-performance TFBs. [ABSTRACT FROM AUTHOR]

Nanoparticles of CuO have been synthesized by the sol-gel technique and their structural, optical and chemical properties were studied to assess their antibacterial properties. These nanoparticles were found to be excellent antibiotic against E.coli and cocci gram-positive. Graphene oxide (GO) nanoparticles were also synthesized by hummers modified method and their optical, chemical and structural properties were confirmed. A composite of CuO and GO has also been prepared by sonication method. Using laser interferometry its ultraviolet (UV)-visible (VIS) spectrum has been observed to be consistent with its reference UV-VIS spectrum, which verified the formation of nanocomposite. The composites were prepared in suspension form, and were used for antibacterial activity, appeared to be a great antibacterial substance against two different types (E.coli and pseudo) of gram-positive bacteria. [ABSTRACT FROM AUTHOR]

CuO pricky microspheres have been synthesized without additives by calcination after hydrothermal treatment at 1 2 0 ∘ C for 6 h. The product was characterized by SEM, TEM, EDS, etc. The unique pricky microspheres were formed with NH4HCO3 and urea as precipitators. Through a series of reaction experiments, the possible formation mechanism of nucleation, growth and secondary growth was proposed. With the assistance of H2O2, the degradation rate of RhB aqueous solution reached 87.16% after 50 min by simulated visible light degradation, which proved the good photocatalytic performance of the CuO pricky microspheres. After four cycles of degradation experiments, the degradation rate of RhB aqueous solution is still above 80%. The radical capture experiments showed that the main active groups in the degradation process were ⋅OH and ⋅ O 2 − , and the mechanism of photocatalytic degradation of Rhb was proposed. [ABSTRACT FROM AUTHOR]

In this experimental work is based on the comparison on the three different nanoparticle mixed nanofluid usage influence on the evacuated tube solar collector (ETSC). The distilled water is initially tested to identify the better performance providing mass-flow rate then the mass-flow rate. There are three nanoparticles such as MWCNT, Al2O3, and CuO were used in to create the nanofluid by two step method to use as a heat transfer fluid in the system. There are four different combinations of nanofluid were created based on the 0.05% of volume fraction of nanoparticles involvement. The corresponding performance parameters such as outlet temperature, maximum absorbed heat and thermal efficiency were measured and calculated. Among that 50% of MWCNT, 40% of Al2O3, and 10% of CuO nanoparticle mixer of 0.05% volume fraction used nanofluid reached the 38.76% higher temperature difference 33.02% more useful heat absorbed and 33.04% of more efficiency than distilled water in the system. [ABSTRACT FROM AUTHOR]

In the present work, a simple two-step method is proposed for mixed oxide synthesis aimed at the achievement of antibacterial nanomaterials. In particular, Cu, Zn and Co have been selected to achieve single-, double- and triple-cation oxides. The synthesized samples are characterized by XRD, IR, SEM and EDX, indicating the formation of either crystalline or amorphous hydrocarbonate precursors. The oxides present one or two crystalline phases, depending on their composition; the triple-cation oxides form a solid solution of tenorite. Also, the morphology of the samples varies with the composition, yielding nanoparticles, filaments and hydrangea-like microaggregates. The antibacterial assays are conducted against E. coli and indicate an enhanced efficacy, especially displayed by the oxide containing 3% Co and 9% Zn incorporated into the CuO lattice. The oxides with the highest antibacterial properties are tested for their cytotoxicity, indicating a low toxicity impact, in line with literature data. [ABSTRACT FROM AUTHOR]

Copper oxide nanowires (NWs) are promising elements for the realization of a wide range of devices for low-power electronics, gas sensors, and energy storage applications, due to their high aspect ratio, low environmental impact, and cost-effective manufacturing. Here, we report on the electrical and thermal properties of copper oxide NWs synthetized through thermal growth directly on copper foil. Structural characterization revealed that the growth process resulted in the formation of vertically aligned NWs on the Cu growth substrate, while the investigation of chemical composition revealed that the NWs were composed of CuO rather than Cu2O. The electrical characterization of single-NW-based devices, in which single NWs were contacted by Cu electrodes, revealed that the NWs were characterized by a conductivity of 7.6 × 10−2 S∙cm−1. The effect of the metal–insulator interface at the NW–electrode contact was analyzed by comparing characterizations in two-terminal and four-terminal configurations. The effective thermal conductivity of single CuO NWs placed on a substrate was measured using Scanning Thermal Microscopy (SThM), providing a value of 2.6 W∙m−1∙K−1, and using a simple Finite Difference model, an estimate for the thermal conductivity of the nanowire itself was obtained as 3.1 W∙m−1∙K−1. By shedding new light on the electrical and thermal properties of single CuO NWs, these results can be exploited for the rational design of a wide range of optoelectronic devices based on NWs. [ABSTRACT FROM AUTHOR]

The present study has investigated the photoresponse of n-MoS2 QDs/n-MoS2/p-CuO, a hybrid dimensional nanoscale heterostructure fabricated on a flexible Ag-coated Kapton substrate. The fabricated flexible heterostructure demonstrates a significant response toward ultraviolet (UV) (376 nm) to near-infrared (NIR) (1064 nm) wavelengths, even in the self-powered mode. The type-II heterostructure formed between the n-MoS2 and p-CuO layers offers the necessary built-in potential for separating and transporting photogenerated electron–hole pairs. The fabricated flexible nanodimensional heterostructure offers responsivities of 28, 54, and 83 μA/W for illuminating radiations in UV, visible, and NIR regions, respectively, in the self-biased mode. The response times [rise time (τr)/fall time (τf)] for the fabricated flexible heterostructure were found to be 81.12 ms/83.47 ms, 77.36 ms/85.73 ms, and 75.62 ms/81.92 ms for the illumination of radiations lying in the UV, visible, and NIR wavelength regions, respectively. The obtained photoresponse demonstrates that the fabricated MoS2 QDs/n-MoS2/p-CuO hybrid dimensional flexible heterostructure will be a potential candidate for the futuristic era of flexible and ultrarapid photodetection applications. [ABSTRACT FROM AUTHOR]

Using the Wien2k code based on Full Potential Linearized Augmented Plane Wave approach, the density functional theory was used to examine the structural and opto-electronic properties of CuO. The 4D-optimize option and the Perdew–Burke–Ernzerhof (PBE)-sol functional are used to optimize the structural parameters. Generalized Gradient Approximation (GGA) with PBE-scheme along with the screened Coulomb interaction (GGA + U) and modified Becke–Johnson (GGA–TB-mBJ) potential was performed for the overall calculations. The computed band energies were taken as the key input to extract the transport properties with the help of the Boltzmann transport equation. In contrast to the gap energy provided by the GGA + U ( E g = 1. 5 7 eV), it is demonstrated that the gap energy produced by the TB-mBJ is ∼ 2. 0 2 eV, which is close to the experimental data. The optical characteristics show a high absorption coefficient in the ultraviolet region, an average transmittance of about 65% in the visible range, which covers a wide spectrum of light, and an average reflectance of about 18% in visible light. At low temperatures, the carrier mobility limits the CuO conductivity, whereas, at high temperatures, the carrier concentration dominates. CuO is a potential material for solar cell applications as an absorbent layer and antireflection coating due to these characteristics. [ABSTRACT FROM AUTHOR]

Abstract Nanotechnology is imperative among the various scientific fields that encompass the contemporary science dealing with the manipulation of structures and particles in the range of 1–100 nm. Broad applications of nanoparticles are investigated by scientists, such as opto-electrical, chemical, medical, environmental, energy sector, etc. Plant-based molecules have been reported to enhance the significance of nanoparticles and their applications owing to the presence of diverse capping and reducing agents. Biogenic route or the Green nanotechnology is clean, nontoxic and eco-friendly, which deserves huge recognition. Three of the most commonly synthesized and reported nanoparticles are of gold, zinc, and copper oxide. This review article details the recent advances in the biogenically synthesized Au, Zn, and Cu oxide nanoparticles. Furthermore, it focuses on the electrochemical aspects of these green nanoparticles to overcome the energy as well as pollution crisis. [ABSTRACT FROM AUTHOR]

Environmental pollution is a global problem and dye pollution is one of the major factors. TiO2 shows promising photocatalytic properties that can degrade organic pollutants such as dye under ultraviolet (UV) irradiation. However, TiO2 possesses some disadvantages such as a wide band gap and a high recombination rate of electron-hole pairs. Coupling TiO2 with various metal oxides can enhance photocatalytic properties. In this work, photodepositon (reduction of metal ions on TiO2) followed by the thermal oxidation method were used for the coupling of TiO2 with CuO, ZnO, or SnO2 under various methanol concentrations (25 vol% or 50 vol%) and deposition duration (1 h or 3 h) to observe the effect of these parameters on the photocatalytic degradation activity on Rhodamine B (RhB) dye (up to 90 min). The rate constant of the photodegradation reaction (k) has improved from 0.0141 min−1 (uncoupled TiO2) to 0.0151~0.0368 min−1. Overall, CuO/TiO2 and SnO2/TiO2 samples have shown similar photocatalytic properties (average rate constants of 0.0341 min−1 and 0.0327 min-1, respectively), and both performed better than ZnO/TiO2 in terms of RhB photodegradation (average rate constants of 0.0197 min−1). The difference in photocatalytic performance can be explained by the bandgap of metal oxides and their relative band positions with TiO2. Lastly, CuO/TiO2 (50 vol%, 3 h) and SnO2/TiO2 (50 vol%, 3 h) have shown the best photocatalytic properties respectively due to a longer deposition time and higher concentration methanol, resulting in more deposited materials. [ABSTRACT FROM AUTHOR]

This contribution demonstrates and discusses the preparation of finely dispersed copper(II) oxide nanosuspensions as precursors for reductive laser sintering (RLS). Since the presence of agglomerates interferes with the various RLS sub-processes, fine dispersion is required, and oversized particles must be identified by a measurement methodology. Aside from the established method of scanning electron microscopy for imaging individual dried particles, this work applies the holistic and statistically more significant laser diffraction in combination with dynamic image analysis in wet dispersion. In addition to direct ultrasonic homogenization, high-energy ball milling is introduced for RLS, to produce stable nanosuspensions with a high fine fraction, and, above all, the absence of oversize particles. Whereas ultrasonic dispersion stagnates at particle sizes between 500 n m and 20 μ m , even after 8 h, milled suspension contains a high proportion of finest particles with diameters below 100 n m , no agglomerates larger than 1 μ m and a trimodal particle size distribution with the median at 50 n m already, after 100 min of milling. The precursor layers produced by doctor blade coating are examined for their quality by laser scanning microscopy. The surface roughness of such a dry film can be reduced from 1.26 μ m to 88 n m by milling. Finally, the novel precursor is used for femtosecond RLS, to produce homogeneous, high-quality copper layers with a sheet resistance of 0.28 Ω /sq and a copper mass concentration of 94.2%. [ABSTRACT FROM AUTHOR]

Antimonous oxide (Sb2O3) has intriguing physical and chemical features that make it useful in various device applications, including solar cells. Nanofilms of Sb2O3:0.02 wt.% CuO were prepared onto glass and silicon substrates etched by laser using a thermal evaporation process in a vacuum, with different thicknesses of about 20, 30, and 40 nm. The deposited nanofilms have no distinguishing peaks in XRD analysis. The broadening of peak shows due to the absence of long-range symmetry; as a result, the nanocrystalline structure is disorganized. Scanning electron microscope analysis of the surface morphology of the formed nanofilms showed to be spread out uniformly and were devoid of islands and voids. The particles were all about the same size, and the new structures were created with a thickness of 40 nm. Atomic force microscopy scanning images showed the nanofilms' homogeneous surface morphology with granular shape. As nanofilm thickness increased, so did average roughness, root mean square value, and grain diameter. Optical characteristics revealed a reduction in the transmittance spectrum with increasing thicknesses. Instead, the optical energy gap ( E g o p t ) was decreased by quantum confinement from 3.56 to 3.48 eV. The electrical properties of the nanofilms were analyzed, and it was found that all were n-type and that mobility (µ) decreased with nanofilm thickness. As shown by the I–V characteristics, the solar cell's conversion efficiency increases to 6.373% at power = 100 mW/cm2 with 0.138 filling factor, 4 V of open circuit voltage, and 2.6 mA of short circuit. [ABSTRACT FROM AUTHOR]

For this article, waste glass cullet obtained from the glass industry was used as a choice of SiO2 substitute in glass manufacturing. A series of soda lime silicate glasses doped with CuO, in composition (55−x) SiO2: 15Li2O: 20Na2O: 10CaO: xCuO (x = 0.00, 0.01, 0.02, 0.03, 0.04, and 0.05 mol%)) were prepared by melt-quenching technique. The parameters such as density and molar volume were measured and evaluated their oscillator strength, refractive index, ion concentration, polaron radius, and inter-nuclear distance. Optical properties such as refractive index, absorption spectra, optical band gab, and CIE L*a*b* were investigated. With increasing of CuO concentration, the density and the refractive index of glasses increased, while the molar volume decreased. The absorption spectra show board peak in the range of 550 to 950 nm. The addition of CuO generated the blue hue in glasses, corresponding to the CIE L*a*b color coordinate. [ABSTRACT FROM AUTHOR]

Energy consumption for building cooling is directly related to incident solar radiation. Therefore, solutions of high reflectivity, while keeping color comfort, are being actively researched. Here, finite-difference time-domain (FDTD) simulations were used to investigate the influence of nanoparticle and core–shell additives on coating reflection and color. Different TiO 2 and CuO nanoparticle mixings were tested, with relative concentrations varying from 0 to 20% of each on acrylic. The same compounds were used to define core–shells with a varied inner radius (0–30 nm) for both TiO 2 and CuO as the core and shell. The numerical simulations demonstrate that mixing CuO with TiO 2 enables dark colors while maintaining the overall reflectance. The reflectance results for the core–shell structure are comparable with those of the nanoparticles when CuO is the core, while a more pronounced color change is originated when CuO is the shell. [ABSTRACT FROM AUTHOR]

In this study, cupric oxide (CuO) nanoparticles (NPs) were synthesized using copper chloride and different concentrations of sodium hydroxide in an aqueous medium without the use of a surfactant or template. The crystal structure, purity, crystallite size, intrinsic strain, stress, and elastic energy of the as-synthesized samples were all determined using x-ray diffraction (XRD). CuO nanoparticles were confirmed to have a monoclinic structure through XRD analysis. From the XRD peak broadening analysis, the crystallite size and intrinsic strain were investigated using the Williamson–Hall plot (WHP), size–strain plot (SSP), and Halder–Wagner (HW) method. To determine physical and micro-structural parameters such as strain, stress, and energy density, the WHP used three different models: the uniform deformation model (UDM), the uniform stress deformation model (USDM), and uniform deformation energy density model (UDEDM). Field-emission scanning electron microscopy (FE-SEM) micrographs revealed leaf-like, flower-like, and network-like morphologies. At room temperature, the optical properties of the CuO NPs were investigated using ultraviolet-visible (UV–Vis) and photoluminescence (PL) spectroscopy. Using Tauc's plot, the estimated optical energy bandgap (Eg) was 3.70–3.80 eV. CuO nano-leaves had a strong green emission peak at 504 nm and a less intense emission peak at 757 nm. [ABSTRACT FROM AUTHOR]

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In dose-response and structure-activity studies, human hepatic HepG2 cells were exposed for 3 days to nano Cu, nano CuO or CuCl2 (ions) at doses between 0.1 and 30 ug/ml (approximately the no observable adverse effect level to a high degree of cytotoxicity). Various biochemical parameters were then evaluated to study cytotoxicity, cell growth, hepatic function, and oxidative stress. With nano Cu and nano CuO, few indications of cytotoxicity were observed between 0.1 and 3 ug/ml. In respect to dose, lactate dehydrogenase and aspartate transaminase were the most sensitive cytotoxicity parameters. The next most responsive parameters were alanine aminotransferase, glutathione reductase, glucose 6-phosphate dehydrogenase, and protein concentration. The medium responsive parameters were superoxide dismutase, gamma glutamyltranspeptidase, total bilirubin, and microalbumin. The parameters glutathione peroxidase, glutathione reductase, and protein were all altered by nano Cu and nano CuO but not by CuCl2 exposures. Our chief observations were (1) significant decreases in glucose 6-phosphate dehydrogenase and glutathione reductase was observed at doses below the doses that show high cytotoxicity, (2) even high cytotoxicity did not induce large changes in some study parameters (e.g., alkaline phosphatase, catalase, microalbumin, total bilirubin, thioredoxin reductase, and triglycerides), (3) even though many significant biochemical effects happen only at doses showing varying degrees of cytotoxicity, it was not clear that cytotoxicity alone caused all of the observed significant biochemical effects, and (4) the decreased glucose 6-phosphate dehydrogenase and glutathione reductase support the view that oxidative stress is a main toxicity pathway of CuCl2 and Cu–containing nanomaterials. [ABSTRACT FROM AUTHOR]

Electrochemical impedance spectroscopy was applied for studying copper oxide (CuO) nanowire networks assembled between metallic microelectrodes by dielectrophoresis. The influence of relative humidity (RH) on electrical characteristics of the CuO nanowire-based system was assessed by measurements of the impedance Z. A slight increase of Z with increasing RH at low humidity was followed by a three orders of magnitude decrease of Z at RH above 50–60%. The two opposite trends observed across the range of the examined RH of 5–97% can be caused by water chemisorption and physisorption at the nanowire interface, which suppress electronic transport inside the p-type semiconductor nanowire but enhance ionic transport in the water layers adsorbed on the nanowire surface. Possible physicochemical processes at the nanowire surface are discussed in line with equivalent circuit parameters obtained by fitting impedance spectra. The new investigation data can be useful to predict the behavior of nanostructured CuO in humid environments, which is favorable for advancing technology of nanowire-based systems suitable for sensor applications.

An aqueous extract of the shade-dried parts of Asparagus aethiopicus L. and Asparagus densiflorus (Kunth) Jessop was used to synthesize copper (CuO) nanoparticles (Cu NPs). UV-visible spectroscopy was performed to assess the formation of Cu NPs. Maximum absorbance was obtained between 310–360 nm, confirming the formation of Cu NPs. CuO NPs were effective against Pseudomonas aeruginosa (ATCC 27853), a gram-negative human pathogenic bacterium. The bacterial growth curve showed that the NPs inhibited bacterial growth. This study was conducted using different parts of the plant, such as the roots, shoots, fruits, and seeds of A. aethiopicus and the roots and shoots of A. densiflorus. The fruit and seeds of A. aethiopicus showed better results than the roots and shoots. Therefore, employing green synthetic processes inhibits the release of harmful by-products. Compared to traditional techniques of NP synthesis, the transition to the extracellular production of CuO NPs utilizing dried biomass appears to be economical and environmentally beneficial.

Although significant advances have been witnessed in the application of nanozymes in recent years, exploring new strategies to enhance the enzyme-like activity of nanozymes is of urgent importance. Herein, we investigate the feasibility of accelerating the peroxidase-like reaction rate of CuO nanostructures through Fe doping. The coprecipitation method was used to synthesize Fe-doped CuO (Fe-CuO) nanozymes, and the results indicate that the diversified valence of Fe benefits the redox reaction driven by CuO-based nanozymes. With the improved peroxidase-like activity, the Fe-CuO nanozyme enables the significant chromogenic oxidation reaction of 3,3′,5,5′-tetramethylbenzidine (TMB), facilitating the construction of a visual sensing platform for the sensitive and selective determination of ascorbic acid. Under optimal conditions, the absorbance at 652 nm decreases linearly with the concentration of ascorbic acid in the range of 5–50 μM, with a limit of detection as low as 4.66 μM. This work exemplifies the activity enhancement for peroxidase-mimicking nanozymes with a metal-doping strategy and provides a broad prospect for the design of more high-performance nanozymes for biosensing applications.

Titanium with apatite-forming ability as well as antibacterial activity is useful as a component of antibacterial dental implants. When Ti was subjected to hydrogen peroxide (H2O2), copper acetate (Cu(OAc)2), and heat (H2O2-Cu(OAc)2-heat) treatments, a network structure of anatase and rutile titanium dioxide (TiO2) and fine copper oxide (CuO) particles was formed on the Ti surface. The resulting samples accumulated a dense and uniform apatite layer on the surface when incubated in simulated body fluid and showed enhanced antibacterial activity against Escherichia coli and Staphylococcus aureus under visible-light irradiation. Electron spin resonance spectra of H2O2-Cu(OAc)2-heat-treated samples showed that hydroxyl radicals (·OH) were generated from the samples, and the concentration of ·OH increased with increasing Cu concentration of the Cu(OAc)2 solution. The enhanced antibacterial activity of these samples under visible-light irradiation may be attributable to the generation of ·OH from samples. These results suggest that Ti implants obtained using H2O2-Cu(OAc)2-heat treatments and subjected to regular or on-demand visible-light irradiation may provide a decreased risk of peri-implantitis.

The ceramic membrane synthesized from fly ash as the base material with the addition of CuO was used as an adsorbent for Cu(II), Zn(II), and Cd(II) ions in an aqueous solution. The effect of CuO on the characteristics and adsorption activity of fly ash-based ceramic membrane has been studied over Cu(II), Zn(II) and Cd(II) ions with different pH of 2–8, contact time of 30–150 min, and initial concentration of metal ions of 0.1–0.7 mmol/L. The adsorption using the batch method was carried out on Cu(II), Zn(II), and Cd(II) ions individually. This study showed that the surface area and the total pore volume of the fly ash-based ceramic membrane with addition of CuO increased to about nearly eight folds and more than three folds, respectively, compared to the original fly ash-based ceramic membrane. However, the pore size of the fly ash-based ceramic membrane with addition of CuO decreased to more than a-half of the original pore size. The optimum adsorption activity of each Cu(II), Zn(II), and Cd(II) ion was achieved at a pH of 4, 6, and 5, respectively. The adsorption kinetics of Cu(II), Zn(II), and Cd(II) ions on the fly ash-based ceramic membrane with addition of CuO followed the second-order pseudo kinetics model. Moreover, the isotherm study on the adsorption of Cu(II), Zn(II), and Cd(II) ions on the fly ash-based ceramic membrane with addition of CuO followed the Langmuir isotherm model. The adsorption capacity of the fly ash-based ceramic membrane with addition of CuO for Cu(II), Zn(II) and Cd(II) ions was 205 mmol/g, 188 mmol/g, and 111 mmol/g, respectively. This study showed clearly that the fly ash-based ceramic membrane with addition of CuO was an effective adsorbent for the adsorption of Cu(II), Zn(II) and Cd(II) ions.

A Kesterite material like CZTS provides the steering to the researcher with their tunable bandgap and high optical coefficient above 104 cm−1 for solar cells. These features make it a suitable material for a single junction solar cell increasing the acceptance as well. In this paper, comparative numerical simulations were performed on a regular base structure of CZTS absorber layer with a CdS buffer layer, a ZnO window layer, and a transparent n-ITO conducting layer with a proposed structure where CZTS absorber layer is replaced by a CZTS and CuO bi-layer using SCAPS-1D software to optimize the efficiency. In addition to that the thickness, defect densities and doping concentrations of the absorber layers and temperature were varied to observe the responses of open-circuit voltage (VOC), short-circuit current (JSC), fill factor (FF) and efficiency (η) of the solar cell. Among the three basic researchs on lost mechanism for kesterite materials, we have focused on improving the back contact interface recombination through an absorber bi-layer combination of CZTS and CuO resulting in increased VOC, Quantum efficiency and carrier generation efficiency approximately by 50 %, 8.94 %, and 34 % respectively, elevating the efficiency of the proposed structure to 19.92 %.

Although the generation of hydrogen by electrolysis of water is cheapest from all other available sources but splitting of water still takes place with sluggish kinetics and is a challenging barrier for H 2 production on large scale. Moreover, research work is still in progress to understand the oxygen evolution reaction (OER) and design the catalysts with improved OER performance. Herein, we report synthesis, characterization, and OER performance of copper oxide/copper sulfide (CuO/CuS) heterostructures and its individual components copper oxide (CuO) and copper sulfide (CuS) as low-cost catalysts for water oxidation. CuO/CuS has been demonstrated to be a stable and effective catalyst that initiates the OER at a potential of 1.49 V. (vs. RHE). The CuO/CuS catalyst drives the OER at only 270 mV overpotential and Tafel slope of 67 mV dec−1 with a current density of 10 mA cm−2 in 1.0 M KOH. CuO/CuS heterostructures outperforms OER performance of previously reported Cu-based catalysts. Long-term stability and performance toward OER are demonstrated by the oxygen evolution at an applied potential of 1.65 V (vs. RHE) over an extended period. This feature brings a favourable, non-noble, highly efficient, and robust OER catalyst. [Display omitted] • Cuo/CuS heterostructures catalyst synthesized for oxygen evolution reaction (OER). • It exhibits enhanced OER performance with overpotential of 270 mV@10 mAcm−2. • Pre-oxidation of water generate active Cu3+ centers which boost OER performance. • Heterostructures provide large surface area which is responsible for enhanced OER. [ABSTRACT FROM AUTHOR]

As an attempt to facilitate the mass production of porous anatase catalysts in industry, in this work, frits with molar ratios of MgO:TiO2:P2O5 = 20:32:24 and an extra addition of CuO (0, 8, 16, and 24 mol%) were first prepared by melt water‐quenching method. The frits were further heat‐ and acid‐treated, forming porous anatase consisting of nanosheets. The study showed that the CuO‐containing samples had increasing crystallization of anatase and even the crystallization of CuO nano‐rods. The easy dissolution of CuO nano‐rods and the abundant grain boundaries in the heat‐treated samples provided path for the acid‐leaching and greatly accelerated the selective dissolution of the crystallized samples, reducing the acid‐leaching time from 48 h for the CuO‐free sample to 3 h for the sample containing 24 mol% CuO to form a similar porous structure. The preformed anatase acted as nucleus to induce the in situ growth of anatase nanosheets. As a result, CuO greatly fastened the formation of porous anatase, making the industrial production of porous anatase possible. [ABSTRACT FROM AUTHOR]

As supported CuO is well-known for low temperature activity, CuO/CeO2 nanosphere catalysts were synthesized and tested for CO oxidation and preferential oxidation of CO (PROX) in excess H2. For the first reaction, ignition was observed at 95 °C, whereas selective PROX occurred in a temperature window from 50 to 100 °C. The catalytic performance was independent of the initial oxidation state of the catalyst (CuO vs. Cu0), suggesting that the same active phase is formed under reaction conditions. Density functional modeling was applied to elucidate the intermediate steps of CO oxidation, as well as those of the comparably less feasible H2 transformation. In the simulations, various Cu and vacancy sites were probed as reactive centers enabling specific pathways. [ABSTRACT FROM AUTHOR]

In this paper, variation in structural, electrical and optical properties of CuO thin films was noted by varying the spinning speed of spin coater. Sol–gel spin coating technique was used to deposit thin films at spinning speeds 3000 rpm to 4500 rpm. X-ray diffraction technique was the base to determine the phase of CuO thin films. UV spectroscopy technique was used to examine the direct and indirect band gap of films and observed that band gap was in range of 2.2 eV to 2.02 eV and 0.98 eV to1.46 eV respectively. It was found that films deposited at 4500 rpm show high absorbance in ultraviolet region and low absorption in visible region. Field emission scanning electron microscope used as surface profiler to measure the thickness of prepared samples. From FESEM it is noted that thickness varies from 239 to 75 nm as the spinning speed increase from 3000 to 4500 rpm. As the spinning speed increases, electrical property of prepared samples also gets increased. From characterization of various techniques, it was concluded that CuO thin films have great potential for application of solar cell. The electrical conductivity and resistivity of prepared films vary from 0.025 to 0.015 S cm−1and37 ohm-cm to 58 Ω-cm respectively. The obtained band gap shows that these samples were suitable for application in solar cell. [ABSTRACT FROM AUTHOR]

In this research, thin film composite structures were used to prepare optoelectronic devices from bare and Bi‐substituted p‐CuO/n‐ZnO systems. The p‐CuO/n‐ZnO composite thin film structures were prepared by the SILAR technique, and the influences of two different Bi contents on the structure and main physical performances of the samples were investigated. The X‐ray diffraction (XRD) technique showed that the composited thin film materials were multiphased in rutile hexagonal (wurtzite) phase (ZnO) and monoclinic tenorite phase (CuO) type crystal structure. The obtained surface morphological results presented that the structure exhibits an almost homogeneous, plate‐like surface distribution, and depending on the increase of Bi concentration, the plate‐like sheet area widens from ~2.5 μm to 10 μm and the layer boundaries decrease. FT‐IR and Raman spectroscopy were used to investigate the various vibration and Raman active phonon modes of Bi:p‐CuO/n‐ZnO nanostructured heterostructures. For a comprehensive analysis of the optical bandgap of the fabricated composite samples, the estimated values were obtained from the Tauc plot. Produced samples exhibited an Ohmic behavior and dc resistivity values of films can be determined via Ohm′s Law. The adjusted sheet resistance value of 11.51 MΩ/sq when the content of Bi 3.0 % in the growth bath. [ABSTRACT FROM AUTHOR]

This paper introduces a method for producing red copper glaze by adding copper oxide (CuO) and silicon carbide (SiC) additives to the base glaze. SiC created a reducing environment in situ and allowed the glaze to be sintered in an oxidizing furnace environment. Nanocrystals are the determinants of the red color of the glaze. The CuO reduction reaction temperature range of SiC produces a reducing environment in the glaze as detected by the method (DSC). The functional group and phase of nanocrystals were determined by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopy. [ABSTRACT FROM AUTHOR]

Binary copper oxides with different copper ion oxidation states including cuprous Cu2O and cupric CuO have already been successfully synthesized by the simple and highly repeatable grow-up technique from the modified copper Cu sheet. By controlling the annealing time and temperature, the copper oxide (CuO, Cu2O) composites were hierarchically formed on Cu surface. All obtained samples were characterized using X-ray diffraction (XRD) spectroscopy and scanning electron microscopy (SEM). The results showed that the modified Cu sheets after annealing in air yielded the mixture of CuO and Cu2O phases. The obtained Cu2O/CuO composites have been used as active photocatalysts to decolourize the 10 ppm dyes rose bengal solution with the degradation efficiency of 73% over a period of 3 h under UV-A irradiation after three uses. These results make them attractive as reusable photocatalytic materials in form of flat sheet. The other testing conditions as pH values and oxidant agent (H2O2) was carried out. It was observed that the photodegradation achieved up to 96% with the presence of H2O2. [ABSTRACT FROM AUTHOR]

The available intermediate liquid phase during cold sintering were very limited. In this paper, deep eutectic solvent prepared by choline chloride and malonic acid was used as an intermediate liquid phase during cold sintering of CuO at different pressures and temperatures. The results show that CuO with a relative density of 88. 2% is obtained by adding w(deep eutectic solvent) = 10% at 400 °C and 540 MPa. The relative density of CuO is increased by 19. 4% after cold sintering compared to dry pressed. Deep eutectic solvent can be used as an intermediate liquid phase during cold sintering of CuO. [ABSTRACT FROM AUTHOR]

The development of highly effective dressing materials for human injuries that meet the complex requirements for clinical examination is still a challenge. In this regard, different biomaterials could be examined for wound dressing targets. Among these materials, polycaprolactone (PCL) is high biocompatible polymeric substance and has been used for numerous pharmaceutical applications. Furthermore, targeting antibacterial behavior could be done by merging additional nanoparticles such as copper oxide (CuO) and vanadium Oxide (V 2 O 5). The scaffolds could be fabricated using the cast method, which is one of the most simple and facile methods. The morphological features and the surface roughness of the fabricated could be examined using X-ray diffraction, Raman spectroscopy, Fourier transform infrared (FTIR), and scanning electron microscopy (SEM) tests. The contact angle plays a significant role in studying the wettability of the scaffolds and the hydrophilic or hydrophobic behavior of the composed films. Besides the antibacterial behavior to evaluate the effectiveness of these scaffolds to protect the injury until the healing. The cell viability against human normal cells to examine the biocompatibility of the proposed compositions. In this regard, the topographical images show a smooth surface with random pores that have diameters in the range of 0.5–1.5 μm for pure PCL while, the porosity decreased with the addition of ginger and V 2 O 5. The blend of CuO/V 2 O 5 /ginger@ PCL represents a noticeable increase in porosity with a diameter between 0.5 and 3 μm. The contact angles were recorded respectively at 55.02°, 54.12°, 53.89°, and 53.71° which refer to the tendency of the scaffolds to the hydrophilic behavior. In addition, the anti-bacterial activity of CuO/V 2 O 5 /ginger@PCL was represented with the diameter of the inhibition zone equal to 17.6±1.2 mm for E. coli and 12.3±1.2 mm for S. aureus. [ABSTRACT FROM AUTHOR]

Thin films of polyimide (PI) and graphene oxide (GO) were exposed to the accelerated Cu-ions with an energy of 1500 keV at different ion fluences (3.75 × 1012; 3.75 × 1014; 1 × 1016) cm−2. The reason for Cu-ion irradiation lies in the modification of thin PI and GO layers and their subsequent use in electronics, photo-catalysis and humidity sensing. It was expected that three ways would primarily carry out modification: i) interaction of the accelerated ions with atoms and electrons of the irradiated films, ii) implantation of Cu ions inside the matrices and their attachment to the structures in the form of CuO, and iii) formation of C and Cu aggregates and Cu nanoparticles in the subsurface layer to form an electrically conductive network. The effects of the interactions of energetic Cu-ions on the PI and GO matrices, including the prediction of the depth of Cu ion penetration, were simulated by SRIM software. Elemental changes, including the depth profiles of implanted Cu-ions, were investigated by Rutherford backscattering spectrometry (RBS) and Elastic recoil detection analysis (ERDA). Changes in the chemical bonding on the PI and GO surfaces were studied by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The effect of energetic Cu-ions on the surface morphology was analyzed by Atomic force microscopy (AFM). For the possible application of PI and GO composites in electronics and sensory, the sheet resistivity were measured by the two- point method and the effect of air humidity on electrical properties was studied. Furthermore, the degradation of Rhodamine B solution in the presence of prepared composites under UV-light irradiation was measured for possible use in photo-catalysis. It was found that the interaction of Cu- ions with the matrix leads to the release of oxygen and hydrogen, resulting in an increase in carbon concentration. The increase in carbon concentration leads to an increase in the electrical conductivity of both materials. The irradiation with Cu ion fluence of 1 × 1016 cm−2 probably formed in PI a subsurface conducting network that reduced the sheet resistivity by almost eleven orders of magnitude. The ion irradiation by Cu ion with fluences below 1 × 1016 cm−2 enhances the photo- catalytic properties of both used materials and the best result was achieved in the case of PI irradiated by the ion fluence of 3.75 × 1014 cm−2. [ABSTRACT FROM AUTHOR]

Three types of CuO with different micro–structures were applied to catalyze the conversion of glycerol to lactic acid. The structure–activity relationship between CuO and its catalytic performance was investigated by combining experiments and theoretical calculations. We demonstrated that two CuO samples (CuO–BCC and CuO–CA), as prepared by calcining copper salts, show larger lattice spacing than that of commercial CuO (CuO–COM). In the catalytic experiments, CuO–BCC, which had the largest lattice spacing (d = 0.2480 nm), exhibited the highest yield of 78.54% for lactic acid. The lattice strain caused by lattice expansion was considered more favorable for CuO–BCC in adsorbing glycerol molecules, thereby improving the conversion of glycerol to lactic acid. The DFT simulation calculation results further prove that CuO–BCC has a larger adsorption energy for glycerol and a smaller thermodynamic energy barrier for the dehydrogenation of glycerol to form the key intermediate products (glyceraldehyde and 1,3-dihydroxyacetone) than CuO–COM. This study demonstrates the role of lattice strain effects in the development of catalysts and provides ideas for catalytic glycerol-selective oxidation studies. [ABSTRACT FROM AUTHOR]

In present work, nanocomposites films of polyethylene oxide (PEO), copper oxide (CuO) nanoparticles and indium oxide (In2O3) nanoparticles have been fabricated for discoloration and photo-degradation of dyes pollutants with high efficiency, few cost, anti-aggregation and high dispersion of nanoparticles. The structural and optical properties of PEO/CuO–In2O3 nanocomposites have been investigated. The structural properties were included the tests: optical microscopic (OM), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The optical properties of PEO/CuO–In2O3 nanocomposites were studied in wavelength range (200–800) nm. The results of optical properties of PEO/CuO–In2O3 nanocomposites showed the absorbance of PEO increases about 57.4% at (λ = 500 nm) and the energy gap of PEO reduces about 41.1% with adding of CuO–In2O3NPs which may be considered as a key for various optical and electronic fields. The optical constant of PEO were improved by adding of CuO NPs and CuO–In2O3 NPs. The PEO/CuO–In2O3 nanocomposites have been utilized for photo-degradation of dyes pollutants. The results showed prepared nanocomposites can be used for excellent photo-degradation of dyes with high efficiency reached 91% and low concentration of nanoparticles. [ABSTRACT FROM AUTHOR]

In present work, the nanostructures of silicon carbide(SiC) and copper oxide(CuO) doped transparent polymer(PVA) were designed to employ in various nanosemiconductors and optics devices with excellent optical and electronic properties compared of others nanosystems. The optimized geometrical parameters, electronic and spectroscopic properties of PVA/SiC/CuO nanostructures were investigated. The optimization parameters included both bonds and angles. The structural and electronic properties involved the (total energy, electronic state, energy gap, electrochemical hardness, electronic softness and electrophilicity) as well as spectral properties, which involved IR and UV–Visible. The results showed good obtained relax for nanocomposites from the used density functional theory (DFT). The results indicated that the nanocomposites have high electronic softness and electrophilicity with lower electrochemical hardness. The addition of SiC leads to decrease the energy gap from 7.184 to 2.604 eV while the addition of CuO reduces the energy gap from 7.184 to 4.229 eV, these global results gave important electronic applications. Finally, the obtained results showed that the PVA/SiC/CuO nonocomposites have good structure, optical and electronic properties which make them can be useful as nanosemiconductors materials to use in many nanoelectronics and optics applications. [ABSTRACT FROM AUTHOR]

In this study, copper oxide (CuO) nanoparticles were incorporate within polyvinyl alcohol (PVA) matrix and CuO–PVA nanocomposite film was fabricated by solution casting technique. In order to synthesize nanoparticles, a cost-competitive and facile approach namely mechanochemical method was implemented. As nanoparticles precursors, pre-determined amount of CuSO4, NaCl, and NaOH were mixed. The mixture was ball-milled in zirconia medium for 10 h at ambient temperature and rotational speed of 300 rpm. The XRD characterization analysis indicated CuO nanoparticles formation by ball milling. The CuO size was estimated to be in the ≈ 37 nm range. SEM images demonstrated the spherical morphology and little agglomeration for the nanoparticles. Furthermore, the bandgap energy of CuO was determined to be 1.84 eV. The CuO content in the nanocomposite was set to be 2, 4, 8, and 10 wt%. Strong interaction between the PVA matrix and CuO nanofiller was confirmed by XRD and FT-IR investigations. Moreover, integration of CuO to the polymer matrix resulted in a decreased PVA crystallinity. The antibacterial behavior of PVA was increased by the addition of nanoparticles, and the CuO–PVA nanocomposite containing up to 4 wt% CuO had desirable antibacterial properties demonstrated against Escherichia coli activity. CuO nanoparticles incorporating to PVA network led to reinforced mechanical and dielectric properties for the nanocomposites. Besides, nanoparticles loading had direct impact on the intensified properties. Tensile strength was enhanced from 85.8 (pure PVA) to 154.9 MPa (PVA-10 wt% CuO). The tensile modulus for neat PVA was 0.9 GPa and raised dramatically to 4.5 GPa for PVA-10 wt% CuO. Dielectric constant also improved more than three times at 1 kHz comparing PVA and PVA-10 wt% CuO. [ABSTRACT FROM AUTHOR]

Highlights: S-doped CuO nanorod arrays (S-CuO/CF) constructed by sulfur leaching and oxidative remodeling strategy require only 1.23 and 1.33 V versus hydrogen evolution reaction (HER) to provide glycerol oxidation currents of 100 and 500 mA cm−2. S-CuO/CF shows satisfactory performance (at 100 mA cm−2, Vcell = 1.37 V) assembled as the anode in asymmetric coupled electrolytic cell of glycerol oxidation reaction and HER. The study identifies the key factors involved in the GOR reaction pathway, which include the C–C bond breaking and lattice oxygen deintercalation steps. Glycerol (electrochemical) oxidation reaction (GOR) producing organic small molecule acid and coupling with hydrogen evolution reaction is a critical aspect of ensuring balanced glycerol capacity and promoting hydrogen generation on a large scale. However, the development of highly efficient and selective non-noble metal-based GOR electrocatalysts is still a key problem. Here, an S-doped CuO nanorod array catalyst (S-CuO/CF) constructed by sulfur leaching and oxidative remodeling is used to drive GOR at low potentials: It requires potentials of only 1.23 and 1.33 V versus RHE to provide currents of 100 and 500 mA cm−2, respectively. Moreover, it shows satisfactory comprehensive performance (at 100 mA cm−2, Vcell = 1.37 V) when assembled as the anode in asymmetric coupled electrolytic cell. Furthermore, we propose a detailed cycle reaction pathway (in alkaline environment) of S-doped CuO surface promoting GOR to produce formic acid and glycolic acid. Among them, the C–C bond breaking and lattice oxygen deintercalation steps frequently involved in the reaction pathway are the key factors to determine the catalytic performance and product selectivity. This research provides valuable guidance for the development of transition metal-based electrocatalysts for GOR and valuable insights into the glycerol oxidation cycle reaction pathway. [ABSTRACT FROM AUTHOR]

The catalytic transfer hydrogenation (CTH) of bio-oil over CuO/PC (porous carbon) with the solid residue produced during biomass pyrolysis as the carrier was investigated with methanol as the hydrogen donor. The effect of carbonization temperature, activation temperature, KOH solution and metal loading on the physicochemical characteristics of CuO/PC catalystand catalytic transfer hydrogenation of bio-oil were investigated. The main alcohols formed in the CTH of bio-oil were 1, 4-butanediol, 1, 3-cyclopentadiol, 1, 3-cyclohexanediol, 2-cyclohexenol and alcohols. It was revealed that more alcohols were produced over CuO/PC using less Cu(NO 3) 2 than Cu 2 Al considering their favorable porous system. The well-developed pore structure is formed in PC at a higher calcination temperature and the concentration of activator, which was favorable for the CTH of bio-oil. Under the optimized preparation conditions, the mesopores accounting for 50% in the total pores, achieving the maximized yield of alcohols of 81%, and the well recycling performance was observed with the overall yield of alcohols decreases within 3% after five cycles because of the greater mesopores ratio. The biochar-based PC catalyst in this work enhances the effective usage of biomass to produce alcohols, fully conforming to the theme of energy conservation and low-carbon times. [Display omitted] [ABSTRACT FROM AUTHOR]

A simple and environmentally‐friendly approach was developed to synthesize 2D CuO nanosheets using electrochemical deposition. The formed 2D CuO nanosheets (NSs) exhibit numerous advantageous properties such as no toxicity, high electrical conductivity, large active surface area, and a p‐type semiconducting nature with a band gap of 1.2 eV. A sensitive electrochemical sensor was constructed for the amperometric detection of glucose to take advantage of these characteristics. The fabricated sensor displayed an excellent sensitivity of 2710 μA mM−1 cm−2 along with a wide linear range of 0.001–1.0 mM and a lower limit of detection of 0.8 μM (S/N=3). Additionally, the modified electrode possesses high selectivity and good stability. The outstanding electrocatalytic performance of the electrode is attributed to a large active surface area, unique structural morphology, and the high conductivity of the 2D CuO nanosheets. [ABSTRACT FROM AUTHOR]

Currently, there is a lack of detailed knowledge about methane (CH4) reactions on metal oxide surfaces. This reaction involves in different processes such as chemical looping combustion and catalytic carbon dioxide (CO2) reforming of CH4. In this study, in situ diffuse reflectance infrared Fourier transform spectroscopy was used to investigate CH4 reaction on three transition metal oxides (CoO, CuO, and α-Fe2O3) which are commonly used in these processes at temperatures ranging from 100 °C to 700 °C. The results show that CH4 is adsorbed on the metal oxide surfaces as methoxy and formate, and then the methoxy group reacts with the metal oxide lattice oxygen forming bicarbonate. Under the effect of the used reaction temperature, the bicarbonate decomposes to CO2 and water vapor. [ABSTRACT FROM AUTHOR]

The paper is a theoretical exploration of complex Al/CuO thermite combustion processes, using a zero‐dimensional (0D) model which integrates both condensed phase and gas phase reactions, and considers all thermodynamic stable molecular or atomic species identified during the Al+CuO reaction. We found that the particle size mainly influences the reaction kinetics and pressure development. Thermite with nano‐sized particles (nanothermites) burns ∼10 times faster than the same thermite with micron‐sized particles (microthermites). This is due to the fact that the thermite reaction occurs mainly in condensed phase, i. e. in the melted Al phase, as all gaseous oxygens released by the CuO decomposition are spontaneously absorbed on the huge specific surface area of metallic Al. As a consequence, the pressure development in nanothermites follows the thermite chemical reaction, the gas phase is mostly composed of a metal vapor (mostly Cu and Al), Al suboxides, but is free of molecular oxygen. In contrast, when dealing with microthermites, an oxygen pressure peak occurs prior to the thermite reaction due to the gaseous O2 released by the early CuO decomposition, that cannot be absorbed on the Al particles surface in real time. The powder stoichiometry greatly impacts the final pressure. Al lean thermites generate a higher final pressure (×3) than stoichiometric and Al rich mixtures, due to unreacted gaseous oxygen which remains in the gas phase after the full consumption of the metallic Al. [ABSTRACT FROM AUTHOR]