Size Of CuO Nanoparticles Research Articles

CuO vs. AgO: A comparative study of cathode catalysts for boosting oxygen reduction in microbial desalination cells

Microbial Desalination Cell (MDC) is an innovative approach for water desalination that concurrently produces energy through the process of substrate oxidation. The primary issue of the technique is its limited power on capabilities during the oxygen reduction reaction (ORR). While the depletion of oxygen is a significant process in electrochemical energy conversion, its slow kinetics hinder its utilization in MDCs. One potential resolution to this problem is the utilization of a cathode catalyst with a high level of activity, which effectively enhances the rate of ORR. Different concentrations of copper oxide (CuO) nanoparticles (NPs) were used to investigate the behavior of ORR and its impact on the performance of the MDC. The optimal concentration of silver oxide (AgO) NPs was utilized to conduct a comparative analysis of both types of NPs. The size of CuO NPs and AgO NPs was found to be 65 nm and 55 nm respectively by material characterization studies. The power density achieved in the absence of the catalyst was 1.1 W/m3, and this value increased to 4.9 W/m3 with the incorporation of 3 mg/cm2 AgO. The use of a catalyst loading of 3 mg/cm2 has been determined to be efficacious in enhancing the desalination rate in MDC. The electrochemical investigations conducted also showed an improvement in the electrocatalytic behavior of cathodic kinetics while operating under these specific afterward. Therefore, the utilization of AgO catalyst exhibits potential as a viable option for the expansion of MDC processes, thereby contributing to the achievement of sustainable development objectives.

Biogenic synthesized copper oxide nanoparticles by Bacillus subtilis: Investigating antibacterial activity on the mexAB-oprM efflux pump genes and cytotoxic effect on MCF-7 cells.

One of the main characteristics of Pseudomonas aeruginosa is remarkable intrinsic antibiotic resistance which is associated with production of β-lactamases and the expression of inducible efflux pumps. Nanoparticles (NPs) are a novel option for coping with this resistant bacteria. Hence, the aim of present study was production of CuO NPs via Bacillus subtilis and applied them to deal with resistant bacteria. For this purpose, first NPs were synthesized and were analyzed with different standard techniques containing scanning electron microscope, Fourier-transform infrared spectroscopy, and X-ray powder diffraction. Microdilution Broth Method and real-time polymerase chain reaction were used to antibacterial properties of the CuO NPs and expression of mexAB-oprM in clinical samples of P. aeruginosa, respectively. The cytotoxic effect of CuO NPs was also evaluated on MCF7 as a breast cancer cell line. Finally, the data were analyzed by one-way analysis of variance and Tukey's tests. The size of CuO NPs was in the range of 17-26 nm and showed antibacterial effect at <1000 μg/mL concentrations. Our evidence noted that the antibacterial effects of the CuO NPs occurred through the downregulation of mexAB-oprM and upregulation of mexR. The interesting point was that CuO NPs had an inhibitory effect on MCF7 cell lines with the optimal inhibition concentration at IC50 = 25.73 µg/mL. Therefore, CuO NPs can be considered as a promising medical candidate in the pharmaceutical industry.

Laser ablation assisted synthesis of graphene/CuO nanocomposite: effect of laser fluence

ABSTRACT The role of laser fluence on the properties of graphene/CuO nanocomposite, prepared by pulsed laser ablation method was studied experimentally. Ablation processes were carried out with the fundamental wavelength of a Q-switched Nd:YAG laser. First, the graphene nanosheets were synthesized by irradiation of a graphite target in distilled water. Then, a Cu target was irradiated by the same laser pulses in the graphene suspension. Three samples of graphene/CuO nanocomposites were formed by different fluences of laser pulse. Results indicate that decoration of graphene with CuO nanoparticles was performed in all nanocomposite samples. As the laser fluence increased, adhesion of graphene nanosheets was enhanced, and the size of CuO nanoparticles was decreased, while the rate of their production was increased. According to the results, it can be concluded that the laser fluence is an effective tool to control the characteristics of laser ablation produced nanocomposites.

Spectral, Structural, and Antibacterial Study of Copper(II) Complex with N2O2 Donor Schiff Base Ligand and Its Usage in Preparation of CuO Nanoparticles

A new Schiff base complex, Cu(H2L)2 (H3L: 6,6 ′ -((1E,1 ′ E)-((azanediylbis(ethane-2,1-diyl))bis(azanylylidene))bis(methanylylidene))bis(2-methoxyphenol)), through the reaction of ligand H3L with Cu(NO3)2 3H2O, in the ratio of 2 : 1 in methanol solvent was prepared. The obtained ligand (H3L) was characterized by FT-IR, 13C NMR, 1H NMR and elemental analyses. Then its copper(II) complex was prepared and characterized by FT-IR spectroscopy, thermal studies, elemental analyses and single crystal X-ray diffraction. The X-ray crystallography revealed that the two H3L ligands in bidentate fashion coordinated to one copper center for producing Cu(H2L)2 complex. We used copper(II) Schiff base complex, Cu(H2L)2, for the preparation of CuO nanoparticles via solid-state thermal decomposition. The crystalline structure of the product was studied by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). XRD indicated that the new product was copper oxide. SEM image showed that the size of CuO nanoparticles was between 46 and 53 nm, and they had uniform shape. The antibacterial properties of the complex and ligand were also investigated. The results revealed that Schiff base complex showed higher biological activity than Schiff base ligand.

Size-Controlled Synthesis of CuO Nanoparticles by the Supercritical Antisolvent Method in SBA-15

Herein, we describe a facile method to control the size and dispersion of CuO nanoparticles (NPs) in SBA-15 by the supercritical antisolvent (SAS) method during the depressurization process of supercritical fluid deposition (SCFD), describing the mass transfer between supercritical carbon dioxide (scCO2) and a cosolvent. On reducing the concentration of the cupric nitrate precursor, the size of CuO NPs was decreased from 3.5 ± 1.0 to 1.0 ± 0.4 nm (Cu loading 14.2–12.1 wt %) under the depressurized rate of ∼20 MPa/min. Based on the size distribution and nucleation theory, the nucleation rate of the precursor could reach 1025 cm–3·s–1, and the calculated interface energy of cupric nitrate was less than 0.1 J/m2, indicating that scCO2 as an antisolvent caused the heterogeneous nucleation of the precursor on the surface of SBA-15 channels. Hence, the nucleation rate and growth of cupric nitrate were regulated under a given scCO2 depressurized rate, and then the CuO NPs’ size distribution and Cu loading were controlled subsequent to calcination.

Scalable microwave-assisted continuous flow synthesis of CuO nanoparticles and their thermal conductivity applications as nanofluids

We have demonstrated the novel and scalable synthesis of CuO nanoparticles by an integration of microwave and flow synthesis. The shape and size of CuO nanoparticles were tuned by changing the concentration of copper precursor. The production rate of CuO nanoparticles was found to be 5 g/h with 70% conversion of copper acetate into the CuO nanoparticles. The thermal conductivity of CuO nanofluid prepared in ethylene glycol showed linear enhancement with increase in the volume content of CuO nanoparticles produced in batch and flow reactors.

Mechanisms of oxidative stress caused by CuO nanoparticles to membranes of the bacterium Streptomyces coelicolor M145

Toxic effects of widely used CuO nanoparticles (NPs) on the genus Streptomyces has been seldom studied. This work investigated toxicities of several sizes of CuO nanoparticles (NPs) to Streptomyces coelicolor M145 (S. coelicolor M145). Compared with NPs, toxicity of micrometer-sized CuO on M145 was trivial. In 0.9% NaCl, when the concentration of CuO NPs was 100 mg/L, survival of bacteria increased from 18.3% in 20 nm particles to 31.1% in 100 nm particles. With increasing concentrations of CuO, the level of ROS gradually increased and there were significant differences (p ＜ 0.05) in ROS exposed to 20, 40 and 100 nm (80 nm) CuO NPs. In TSBY medium, toxicity of CuO NPs was less and mainly attributed to release of Cu2+, analysis by confocal laser scanning microscope (CLSM) showed that size of the mycelium did not change although some individual bacteria died. This was likely due to Cu2+ released from NPs entering cells through the membrane, while in 0.9% NaCl, lesions on membranes was caused by NPs outside the bacteria. This research indicated that toxicity of CuO NPs to S. coelicolor, is related to both size of NPs and is dependent on characteristics of the medium. CapsuleThis is the first time to measure the toxicity of nano materials to Streptomyces, and toxic CuO NPs to Streptomyces have been shown to differ depending on medium.

Doped Poly(m-phenylenediamine-co-aniline) (P(mPD-co-ANI)): Synthesis, Characterization, Physical Properties, and Precursor for CuO Nanoparticles

ABSTRACTPoly(m-phenylenediamine-co-aniline) P(mPD-co-ANI) and Mn-, Ni-, and Cu-doped poly(m-phenylenediamine-co-aniline) (M-P(mPD-co-ANI)) have been synthesized and characterized. Cu-P(mPD-co-ANI) has been used as a molecular precursor of CuO nanoparticles. The spectral, optical, refractive index, solubility, and thermal properties of the synthesized polymers have been measured and discussed. The optical bandgap (Eg) measurements indicated that Ni(P(mPD-co-ANI)) has wider optical band than the pure (P(mPD-co-ANI)). Calcination of Cu-P(mPD-co-ANI) at 600°C produced (CuO) nanoparticles. The obtained nanoparticles have been characterized by XRD and TEM. The average size of CuO nanoparticles was found to be 42 nm. The refractive index measurements indicate slight change in the refractive index values of the polymer solution than that of pure solvent. The solubility of the synthesized polymers in ethanol, dimethyl formamide (DMF)–aqueous mixed solvents was found to increase as the mole fractions of both ethanol and DMF increase. The UV spectra of the synthesized polymers in ethanol, DMF–aqueous mixed solvents indicate blueshift and hyperchromic effect.

Synthesis and characterization of silica-, meso-silica- and their functionalized silica-coated copper oxide nanomaterials

Silica- or meso-silica- or silica-meso-silica-coated copper oxide microspheres were prepared based on base hydrolysis of tetraethyl orthosilicate in the presence of CuO and CTAB. Functionalization with amine or thiol organofunctional groups was conducted onto the surface of silica-meso-silica-coated copper oxide microspheres (Scheme 1). The silica-coated CuO composites and their amine- or thiol-functionalized materials have been characterized by TEM, XRD, TGA, FTIR and UV/Vis. TEM analysis showed that the CuO nanoparticles were encapsulated and dispersed into the silica or meso-silica microspheres. XRD analysis indicated that the size of CuO nanoparticles has decreased after coating with silica precursors. TGA and FTIR results indicated that the meso-silica-coated copper oxide materials have been successfully grafted by amine and thiol organofunctional groups.

Heterogeneous magnetic state in nanocrystalline cupric oxide CuO

This paper presents the results of investigations of the structural state and magnetic properties of nanocrystalline cupric oxide samples with average particle sizes of approximately 40 and 13 nm, which were synthesized by the electric explosion and gas phase methods, respectively. The samples have been studied using X-ray diffraction, neutron diffraction, magnetic measurements, high-resolution transmission electron microscopy, and copper nuclear magnetic resonance. It has been shown that, in the initial state, regardless of the synthesis method, CuO nanoparticles are characterized by a heterogeneous magnetic state, i.e., by the existence of long-range antiferromagnetic order, spontaneous magnetization, especially at low temperatures, and paramagnetic centers in the material. The ferromagnetic contribution is probably caused by the formation of magnetic polaron states due to the phase separation induced in the system by excess charge carriers as a result of the existence of point defects (vacancies in the anion sublattice) in the nanocrystalline state. In this state, there is an inhomogeneously broadened nuclear magnetic resonance spectrum, which is a superposition of the spectrum of the initial antiferromagnetic matrix and the spectrum of ferromagnetically ordered regions. At high concentrations of ferromagnetically ordered regions, the antiferromagnetic matrix exhibits a nuclear magnetic resonance spectrum of CuO nanoparticles, predominantly from regions with the ferromagnetic phase. The appearance of magnetization can also be partly due to the frustration of spins in CuO, and this state is presumably localized near the most imperfect surface of the nanoparticles. The magnetic susceptibility of nanoparticles in the initial state in strong magnetic fields is significantly higher than that for the annealed samples, which, most likely, is associated with the influence of the high concentration of magnetic polarons. No correlation between the ferromagnetic contribution and the size of particles is found. In the CuO samples annealed at 400°C in air, when the average size of CuO nanoparticles remains unchanged, the ferromagnetic contribution completely disappears, and the magnetic behavior of the nanoparticles becomes qualitatively similar to the magnetic behavior of bulk CuO.

ChemInform Abstract: Nano CuO‐Catalyzed C—H Functionalization of 1,3‐Azoles with Bromoarenes and Bromoalkenes.

AbstractCompound (Ia) does not react with phenylchloride instead of phenylbromide (II).