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Nickel-substituted copper oxide nanoparticles at various concentrations were synthesized by the microwave irradiation technique. The consequence of nickel doping on crystal structure, optical properties, and magnetic properties was examined by means of X-ray diffractometer, ultraviolet-visible spectrometer, Fourier transform infrared (FT-IR) spectrometer, transmission electron microscope, and vibrating sample magnetometer (VSM). X-ray diffraction analysis shows that the samples are monoclinic and their crystallite size varies from 25nm to 42nm, and lattice constant significantly increases with nickel concentration. Additional increase of nickel content (7%) decreases the lattice constant. TEM micrograph witnessed that the prepared nanoparticles were sphere-shaped and the particle distribution is in the range between 20 and 40nm. Bandgap measurement reveals that both undoped and nickel-doped copper oxides are direct bandgap semiconductor materials with bandgaps of 3.21 and 3.10eV, respectively, FT-IR spectra of the synthesized samples confirmed the nickel doping. VSM studies confirmed the ferromagnetic behavior of the synthesized samples at room temperature. The results revealed that the nickel-doped copper oxide nanoparticles synthesized via the microwave irradiation method exhibit better magnetic properties than the undoped copper oxide.

The copper oxide, CuO, and copper hydroxide, Cu(OH)₂ nanomaterials have been prepared by a simple copper salt aqueous solution reaction. The powder X-ray diffraction (XRD) analysis showed the successful formation of Cu(OH)₂ and CuO nanoparticles. The average crystallite size of these Cu(OH)₂ and CuO nanoparticles was estimated and found to be around 17nm (Cu(OH)₂) and 10nm (CuO). The surface morphology and size of the CuO particles were confirmed by Scanning Electron Microscope (SEM) and High-resolution transmission electron microscope (HRTEM). The Raman analysis, dielectric and conductivity of CuO nanoparticles have been performed. The frequency variation of the capacitance (real dielectric constant) and dielectric loss was studied. The capacitance of the CuO nanoparticles is high at low frequencies and decreases rapidly when the frequency is increased. The frequency dependent ac conductivity follows Johnscher’s power law.

In this research, an attempt is made to prepare an organic–inorganic hybrid material that aims to improve some of the physical properties of polymeric mixtures composed of polyethelyne oxide (PEO) and polystyrene (PS) by adding copper oxide (CuO) nanoparticles to the single polymers as well as by adding them to the mixture whereby 5% of nanoparticles were added to the polymer. The effect of the addition was studied by SEM and UV–Visible spectrophotometer. The energy band gaps attained by Tauc equation proved that the energy bandgaps are (from 4.4, 3.1 and 3.1eV) for nanocomposites.

Researchers are interested in green technology because it is a low-risk, eco-friendly and affordable way to biosynthesize nanoparticles (NPs). Copper nitrate trihydrate and Nigella sativa extract were used as a reducing and capping agent during the manufacture of copper oxide (CuO) NPs in this investigation. The biosynthesized CuO NPs were characterized using X-ray diffractometer, transmission electron microscopy, UV–Vis spectroscopy, scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The good crystalline nature perfectly matches the monoclinic structure of bulk CuO. The results obtained from TEM also showed that CuO NPs were semi-spherical in shape, while the zeta potential characterization indicated that the prepared particles have low stability. Moreover, CuO NPs showed good antimicrobial activity.

A copper oxide (CuO) nanoparticle, a transition metal oxide with a wide variety of easy production methods, can be used as an antimicrobial agent against various types of bacteria. CuO nanoparticles were produced by the sol–gel method, annealed and structural characteristics and antimicrobial properties of these particles were investigated. Single-phase monoclinic of CuO nanoparticle formation was confirmed by X-ray powder diffraction (XRD) spectra, FTIR techniques, differential scanning calorimetry with thermal gravimetry were used to characterize. It was determined that annealing in the temperature range of 150–900^∘C affects both structure and particle size and antimicrobial characteristics. CuO nanoparticle size was found to be between about 25–70nm at 150–900^∘C annealing temperature, which does not have this wide temperature range in the literature. These results were supported by the TEM micrographs of the CuO nanoparticles observed at 150^∘C and 900^∘C. The antimicrobial activity of the synthesized nanoparticles was tested with the disc diffusion assay against Staphylococcus aureus, Escherichia coli, Agrobacterium tumefaciens, and yeast Pichia pastoris. The antimicrobial properties of the nanoparticles first increased and then decreased and disappeared as the annealing temperature increased. The antimicrobial properties of CuO nanoparticles disappeared at 750^∘C and above, while the maximum antimicrobial effect was at 300^∘C. The inhibition zones were examined and similar results were observed in all tested microorganisms.

Particle size effects on the electrochemical performance of the CuO particles toward lithium are essential. In this work, a low-cost, large-scale production but simple approach has been developed to fabricate CuO nanoparticles with an average size in ~ 130 nm through thermolysis of Cu(OH)₂ precursors. As anode materials for lithium ion batteries (LIBs), the CuO nanoparticles deliver a high reversible capacity of 540 mAh g^-1 over 100 cycles at 0.5 C. It also exhibits a rate capacity of 405 mAh g^-1 at 2 C. These results suggest that the facile synthetic method of producing the CuO nanoparticles can enhance cycle performance, superior to that of some different sizes of the CuO nanoparticles and many reported CuO-based anodes.