Formation of uniform CuO nanorods by spontaneous aggregation: Selective synthesis of CuO, Cu2O, and Cu nanoparticles by a solid-liquid phase arc discharge process

Uniform and monodisperse CuO nanorods have been synthesized by directional aggregation and crystallization of tiny CuO nanoparticles generated from a solid-liquid arc discharge process under ambient conditions in the absence of any surfactants. Uniform CuO nanorods with sharp ends are formed from tiny nanoparticles via a process that involves the rapid oxidation of Cu nanoclusters, the spontaneous aggregation of CuO nanoparticles, and the Ostawald ripening process. The spontaneous aggregation and oriented attachment of tiny CuO nanoparticles contributed obviously to the formation of these kinds of nanostructures. By choice of suitable reducing agent to prevent the oxidation of Cu nanoclusters, Cu and Cu2O nanoparticles can be selectively synthesized.     

Hydrothermal synthesis of CuO micro-/nanostructures and their applications in the oxidative degradation of methylene blue and non-enzymatic sensing of glucose/H2O2

In this paper, we report on the amino acids-/citric acid-/tartaric acid-assisted morphologically controlled hydrothermal synthesis of micro-/nanostructured crystalline copper oxides (CuO). These oxides were characterized by means of X-ray diffraction, nitrogen sorption, scanning electron microscopy, Fourier transform infrared, and UV-visible spectroscopy. The surface area of metal oxides depends on the amino acid used in the synthesis. The formation mechanisms were proposed based on the experimental results, which show that amino acid/citric acid/tartaric acid and hydrothermal time play an important role in tuning the morphology and structure of CuO. The catalytic activity of as-synthesized CuO was demonstrated by catalytic oxidation of methylene blue in the presence of hydrogen peroxide (H(2)O(2)). CuO synthesized using tyrosine was found to be the best catalyst compared to a variety of CuO synthesized in this study. CuO (synthesized in this study)-modified electrodes were used for the construction of non-enzymatic sensors, which displayed excellent electrocatalytic response for the detection of H(2)O(2) and glucose compared to conventional CuO. The high electrocatalytic response observed for the CuO synthesized using tyrosine can be correlated with the large surface area, which enhances the accessibility of H(2)O(2)/glucose molecule to the active site that results in high observed current. The methodology adopted in the present study provides a new platform for the fabrication of CuO-based high-performance glucose and other biosensors.     

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.     

A comparative study of CuO/TiO_2-SnO_2,Cut/Tit_2 and CuO/SnO_2 catalysts for low-temperature CO oxidation

Nanometer SnO2 particles were synthesized by sol-gel dialytic processes and used as a support to prepare CuO supported catalysts via a deposition-precipitation method. The samples were characterized by means of TG-DTA, XRD, H2-TPR and XPS. The catalytic activity of the CuO/TiO2-SnO2 catalysts was markedly depended on the loading of CuO, and the optimum CuO loading was 8 wt.% (T100 = 80 ◦C). The CuO/TiO2-SnO2 catalysts exhibited much higher catalytic activity than the CuO/TiO2 and CuO/SnO2 catalysts. H2-TPR result indicated that a large amount of CuO formed the active site for CO oxidation in 8 wt.% CuO/TiO2-SnO2 catalyst.     

纳米氧化铜催化化学发光性能及其氨基酸检测

用低热固相配位化学反应制得纳米氧化铜并对其进行了透射电镜和X射线衍射表征,得到的纳米氧化铜平均粒径为10nm。用制得的纳米氧化铜催化精氨酸和天冬氨酸的鲁米诺化学发光体系,催化性能较分析纯氧化铜和硫酸铜溶液分别提高了5．65和4．51倍。氨基酸的检出限达10^-9mol／L。     

Investigation into the significant effect of CuO additive on the synthesis of ZrSiO4: phase formation and crystallization at low temperature

Journal of Thermal Analysis and Calorimetry - The ZrSiO4 has been synthesized with CuO as mineralizer by sol–gel route at low temperature. The mineralization effect of the CuO on mechanism of...     

Band structure tuning of ZnO/CuO composites for enhanced photocatalytic activity

The toxic dye pigments, even in small quantities, can damage ecosystems. Removing organic, inorganic, and microbiological contaminants from wastewater via heterogeneous photocatalysis is a promising method. Herein, we report the band structure tuning of ZnO/CuO nanocomposites to enhance photocatalytic activity. The nanocomposites were synthesized by a chemical approach using step-wise implantation of p-type semiconductor CuO to n-type semiconductor ZnO. Various characterization techniques such as X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX) and UV spectroscopy were used to investigate the crystal structure, surface morphology, elemental composition and optical properties of the synthesized samples. As the CuO content increased from 10% to 50% in ZnO/CuO nanocomposites, the optical bandgap decreased from 3.36 to 2.14 eV. The photocatalytic activity of the samples was evaluated against the degradation of methylene blue (MB) under visible irradiation. Our study demonstrates a novel p–n junction oxide photocatalyst based on wt. 10% CuO/ZnO with superior photocatalytic activity. Effectively 66.6% increase in degradation rate was achieved for wt. 10% CuO/ZnO nanocomposite compared to pure ZnO nanoparticles.     

Self-assembled CuO nanoarchitectures and their catalytic activity in the thermal decomposition of ammonium perchlorate

CuO shuttle-like and flower-like nanocrystals were synthesized through a one-step, low-temperature solution-phase method in the presence of a cation surfactant, hexadecyl trimethyl ammonium bromide. These nanocrystals were studied as an additive for promoting the thermal decomposition of ammonium perchlorate (AP). With the addition of CuO shuttle-like and flower-like nanocrystals, the thermal decomposition temperature of AP decreased. The structure, particle size, and morphology of resulting CuO powders were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Thermogravimetric analysis technique was applied to investigate the thermal decomposition of mixtures of AP and as-prepared CuO nanocrystals.     

Sonochemical Coatings of ZnO and CuO Nanoparticles Inhibit Streptococcus mutans Biofilm Formation on Teeth Model

Antibiotic resistance has prompted the search for new agents that can inhibit bacterial growth. We recently reported on the antibiofilm activities of nanosized ZnO and CuO nanoparticles (NPs) synthesized by using sonochemical irradiation. In this study, we examined the antibacterial activity of ZnO and CuO NPs in a powder form and also examined the antibiofilm behavior of teeth surfaces that were coated with ZnO and CuO NPs using sonochemistry. Free ZnO and CuO NPs inhibited biofilm formation of Streptococcus mutans . Furthermore, by using the sonochemical procedure, we were able to coat teeth surfaces that inhibited bacterial colonization.     

Morphologically controlled synthesis of copper oxides and their catalytic applications in the synthesis of propargylamine and oxidative degradation of methylene blue

Alcohol/nonionic polymeric surfactant assisted, morphologically controlled synthesis is developed for micro-/nanostructured crystalline copper oxide. Materials were characterized by a complementary combination of X-ray diffraction (XRD), nitrogen sorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and UV-visible spectroscopy. XRD and FT-IR confirm the formation of a mixture of Cu(OH)₂ and CuO after 0.5 h of hydrothermal treatment and pure CuO after 2 h of hydrothermal treatment. The formation mechanisms were proposed based on the SEM and TEM analysis, which show that both, alcohol/polymeric surfactant and hydrothermal time play an important role in tuning the morphology and structure of CuO. Surface area of metal oxides depends on the alcohols and the nonionic polymeric surfactants used in the synthesis. Surface area of CuO synthesized using methanol was found to be the highest. The catalytic activity of as-synthesized CuO was demonstrated by using three-component coupling reaction in the synthesis of propargylamine and catalytic oxidation of methylene blue in the presence of hydrogen peroxide. Among the CuO prepared in this study, the CuO synthesized using methanol exhibited better catalytic activity (propargylamine yield (64.5%)) and the highest rate of methylene blue degradation (13 × 10⁻³ min⁻¹).     

Syntheses of CuO nanostructures in ionic liquids

A simple and efficient approach is developed to fabricate single-crystalline CuO nanostructures through an ionic liquid assisted one-step low-temperature solid-state route.Both nanoparticles(5 nm in size)and nanorods(5-10 nm in diameter and 50-100 nm in length)of monoclinic CuO were obtained. These synthesized CuO nanostructures were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),selected area electron diffraction(SAED),X-ray photoelectron spectros- copy(XPS),energy dispersive spectroscopy(EDS)and nitrogen adsorption analysis.The morpholo- gies of the nanostructures can be controlled by tuning the amount of NaOH and ionic liquids.The growth mechanism of CuO nanostructures is investigated.     

Cumene Liquid Oxidation to Cumene Hydroperoxide over CuO Nanoparticle with Molecular Oxygen under Mild Condition

CuO nanoparticle was synthesized via wet chemical method and was characterized by X-ray diffraction(XRD),nitrogen adsorption-desorption,and scanning electron microscopy(SEM).Catalytic oxidation of cumene with molecular oxygen was studied over CuO nanoparticle.The catalysts showed markedly higher activities as compared to CuO prepared by conventional method,CuO/Al_2O_3,or ho- mogeneous copper catalyst under comparable reaction conditions.The cumene conversion,comene hy- droperoxide(CHP)yield,and selectivity using 0.25 g CuO nanoparticle catalyst and 0.1 mol cumene at 358 K for 7 h were 44.2%,41.2% and 93.2%,respectively.The catalyst can be recycled.After 6 recycled experiments,no loss of catalytic activity was observed.     

Ranolazine-functionalized CuO NPs: efficient homogeneous and heterogeneous catalysts for reduction of 4-nitrophenol

In the present study copper oxide nanoparticles (CuO NPs) were synthesized using a hydrothermal method with ranolazine as a shape-directing agent. Ranolazine-functionalized CuO NPs were characterized by various analytical techniques such as scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The SEM pattern confirmed the morphology of ranolazine-functionalized CuO NPs with well-defined rice-like structures. FTIR spectroscopy confirmed the interaction between CuO NPs and ranolazine. The XRD analysis indicated that the structure of ranolazine-functionalized CuO NPs was monoclinic crystalline and the size ranged between 9 and 18 nm with an average particle size of 12 nm. The smaller size range of CuO NPs gave a large surface area that enhanced the efficiency of these catalysts employed for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the H ₂ O system. In homogeneous catalysis, results showed that 50 μL of CuO NPs was required in the presence of NaBH4 for 99% reduction of 4-NP in 240 s. On the other hand, for heterogeneous catalysis, 0.5 mg of CuO NPs was used in the presence of NaBH4 for 99% catalytic reduction of 4-NP to 4-AP in 320 s. The rate of reaction for homogeneous catalysis and heterogeneous catalysis was determined from the plots of In(Ct /C0) of 4-NP versus time (s), which showed good linearity with values of 1.3 × 10 ^-2 and 8.8 × 10 ^-3 s ^-1 . respectively. The high-quality catalytic efficiency, good reusability, nontoxic nature, and low cost are favorable properties of the synthesized CuO NPs for use as efficient catalysts for reduction of 4-AP to 4-NP in both homogeneous and heterogeneous media.     

Visible light driven photocatalytic activity of ZnO/CuO nanocomposites coupled with rGO heterostructures synthesized by solid-state method for RhB dye degradation

Metal oxide frame works along with carbon materials have been attracting tremendous attention of researches as the potential materials for energy and environmental remediation. In the present work heterostructures of (ZnO/CuO)/rGO ternary nanocomposites were synthesized by solid-state method. The crystalline structure of the nanoparticles was obtained from the XRD analysis. Optical band gap of the ZnO nanoparticles (3.1 eV) is tuned to 2.8 eV in the synthesized (ZnO/CuO)/rGO ternary nanocomposites. Field emission scanning electron microscope images of the (ZnO/CuO)/rGO ternary nanocomposites revealed formation of well-developed flowers like morphology of (ZnO/CuO) nanoparticles on rGO sheets. Photoluminescence spectroscopy analysis of (ZnO/CuO)/rGO ternary nanocomposites show enhancement in the electron-hole pair separation and thereby diminishing electron-hole pairs recombination rates effectively. In the present work, the photocatalytic activity of the ZC₃G₁₅ ternary nanocomposites show 99% and 93% of degradation efficiency respectively against RhB dye and 4-chlorophenol for 20 min under visible light irradiation. Thus, the simple solid-state method provides the effective ternary nanocomposites heterostructures light harvesting material for energy and environmental remediation.     

Well-aligned arrays of CuO nanoplatelets

This paper reports well-aligned arrays of CuO nanoplatelets synthesized through a hydrothermal route without template's assistance. The surface of well-aligned arrays of CuO nanoplatelets looks like a wall. These nanoplatelets, possessing four clear edges, are 50-80 nm in thickness, 150-250 nm in width, and 0.8-1.5 microm in length. Electron microscopic detection shows that the nanoplatelet grows along the [010] direction. The Ostwald ripening mechanism has been used to describe the growth of CuO nanoplatelets. In addition, the optic and electrochemical properties of as-obtained products have been discussed. And the arrays of CuO nanoplatelets exhibit the blue shift in UV-visible spectra, a slow capacity fading rate, and a relatively high Coulombic efficiency in charge-discharge process.     

Vertically Aligned CuO Nanowires Based Electrode for Amperometric Detection of Hydrogen Peroxide

Vertically aligned copper oxide (CuO) nanowires were synthesized by directly heating copper foil on a hotplate under ambient conditions. The as‐grown CuO nanowires film is mechanically stable and was facilely attached to a glassy carbon (GC) electrode, offering an excellent electrochemical sensing platform. The CuO nanowires electrode shows excellent electrocatalytic response to H₂O₂ with significantly lower overpotentials for its oxidation and reduction and also exhibits a fast response and high sensitivity for the amperometric detection of H₂O₂. The novel vertically aligned CuO nanowires electrode is readily applicable to other analytes and has great potential applications in the electrochemical detection.     

吸附法制备CuO-Ag/SiO2纳米复合物

利用吸附法原位制备CuO/SiO2、CuO-Ag/SiO2纳米复合物,研究了不同吸附质体系中预负载的纳米Ag粒子对CuO的影响。结果表明:Ag粒子对CuO的影响因吸附质的不同而不同。以Cu(Ac)2为吸附质,纳米Ag几乎没有影响;以NaOH为吸附质,纳米Ag使得CuO的晶粒粒径增大。这一结果与铜物种对Ag晶粒粒径的影响规律完全不同。通过比较不同吸附质的吸附行为,Cu(OH)2与硅胶表面的相互作用被认为是导致这一现象的原因。     

采用燃烧技术制备CuO纳米粒子:一种高效且环境友好的用于芳族醛合成芳族腈催化剂(英文)

CuO nanoparticles were synthesized using an energy-efficient and rapid solution combustion technique with malic acid employed as a fuel. The combustion-derived CuO nanoparticles were used as catalysts in a one-pot synthesis of aromatic nitriles from aromatic aldehydes and hydroxylamine hydrochloride. The catalyst was characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, and Brunauer-Emmett-Teller surface area analysis. The catalytic activity of the CuO nanoparticles in the synthesis of aromatic nitriles from aromatic aldehydes was evaluated. The present protocol offers the advantages of a clean reaction, simple methodology, short reaction duration (1-2 min), and high yield (85%-98%). The catalytic activity of the CuO nanoparticles was found to be higher than that of bulk CuO powder under the same conditions. The catalyst can also be recovered and reused up to four times with no significant loss of catalytic activity. The present approach is inexpensive and is a convenient technique suitable for industrial production of CuO nanoparticles and nitriles.     

Effect of CeO2 preparation method and Cu loading on CuO/CeO2 catalysts for methane combustion

CeO2 was synthesized by sol-gel, hydrothermal, nitrate thermal decomposition methods, respectively, and used as support to prepare CuO/CeO2 catalysts. According to characterization and reaction results, preparation method of CeO2 had a great influence on the physicochemical properties and activities of CuO/CeO2 catalysts. CuO with high dispersion and strong interaction with CeO2 was highly active in methane combustion, while CuO particles less associated with CeO2 showed less activity. The CuO catalyst supported on CeO2 which was prepared via nitrate thermal decomposition method showed the largest area, the smallest particle size, the highest dispersion of copper species and strong support metal interactions. Therefore, it presented the highest redox ability and activity for methane combustion. Activities of the catalysts with different copper content kept increasing until 5% Cu loading and from then on kept constant. Moreover, methane conversion decreased as methane space velocities increased on CuO/CeO2 catalyst. Addition of CO2 to the feed did not produce a significant effect on the catalytic activity, but the presence of H2O provoked a remarkable decrease on the activity of CuO/CeO2 catalyst.     

Solar light assisted degradation of dyes and adsorption of heavy metal ions from water by CuO–ZnO tetrapodal hybrid nanocomposite

We report a facile and economic hydrothermal process for multifunctionally engineered copper oxide/zinc oxide-tetrapods (CuO/ZnO-T) nanocomposite for wastewater treatment. The resultant CuO/ZnO-T nanocomposite possesses high porosity, large surface area, and low band gap. All these properties are advantageous for photocatalyst and adsorbent for dyes and heavy metal ions removal. The morphology of synthesized nanocomposite was characterized using X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller, Fourier-transform infrared spectroscopy, and UV–Visible absorption spectroscopy. The results confirmed the attachment of CuO on the ZnO-T surface, forming a hybrid nanocomposite. The concentration of heavy metal ions was monitored using the atomic absorption spectroscopy technique. The synthesized CuO/ZnO-T nanocomposite was investigated for the decontamination of anionic and cationic dyes, Reactive yellow-145 (RY-145) and Basic violet-3 (BV-3) and heavy metal ions (Chromium (VI) and Lead (II)). The CuO/ZnO-T nanocomposite exhibited superior photocatalytic efficiency (80% RY-145 dye removal and 86% BV-3 dye removal) and adsorption capacity (99% Chromium (VI) removal and 97% Lead (II) removal) as compared to pristine ZnO-T. The mechanism for the reduction of dyes and heavy metal ions was discussed by different kinetics and isotherm models. The current study inferred that CuO/ZnO-T nanocomposite is a potential candidate as a proficient photocatalyst/adsorbent for the removal of various wastewater contaminants.