Pure Cupric Oxide Research Articles

Improving field emission properties of CuO nanowires by coating with ZnO nanoparticles

A facile solution route of self-assembled zinc oxide (ZnO) nanoparticles (NPs) on the surface of cupric oxide (CuO) nanowires (NWs) was presented, and field emission arrays with ZnO NPs–CuO NWs hybrid emitters were fabricated. The NW based conjugation by coating ZnO NPs on CuO NWs was confirmed by transmission electron microscopy (TEM) image. The turn on electric fields of the ZnO NPs–CuO NWs hybrid emitters decreased to 2·37 V μm−1 compared with 4·95 V μm−1 of pure CuO NWs, and the field enhancement factor was significantly enhanced from ∼869 (pure CuO NWs) to ∼1678 (ZnO NPs–CuO NWs). The ZnO–CuO NWs hybrid emitters also have higher emitting uniformity, which indicated the efficient field emission properties for the hybrid emitters.

Microwave-assisted synthesis and optical properties of cuprous oxide micro/nanocrystals

Cuprous oxide micro/nanocrystals were fabricated by a facile and green microwave-assisted method using soluble starch as reductant and dispersant. It was observed that the addition amounts of NaOH had a prominent effect on the morphologies and size of cuprous oxide products, and microwave heating was proved to be a efficient method and was advantageous to the homogeneous nucleation. The as-obtained samples were characterized by X-ray diffraction (XRD), and field-emission scanning electron microscopy (FESEM). The results indicated that the samples were pure cuprous oxide. Spheres with the diameter of about 100 and 600nm, octahedron and truncated octahedron with the edge length of about 0.8–3μm cuprous oxide micro/nanocrystals were successfully obtained. Furthermore, the UV–vis diffuse reflectance spectroscopy was used to investigate the optical properties of the prepared cuprous oxide microcrystals, demonstrating that their band gaps of obtained samples were 1.96–2.07eV, assigned to their different sizes and morphologies.

In situ synthesis and assembly of copper oxide nanocrystals on copper foil via a mild hydrothermal process

Different dimensional cupric oxide (CuO) nanocrystals and their architectures have been prepared on copper foil via a mild hydrothermal process with the introduction of different types of surfactants. The X-ray powder diffraction (XRD) and energy dispersive X-ray (EDX) patterns indicate that the products are pure CuO and of monoclinic symmetry. Furthermore, the selected area electron diffraction (SAED) pattern and high-resolution transmission electron microscope (HRTEM) reveal that the products are single-crystalline in nature. Series of experiments confirm that the type of surfactant, the concentration of the surfactant, the concentration of the reactants and the reaction temperature play important roles in the morphology and nanoarchitecture of the products.

Room‐Temperature Electrochemical Assembly of Copper/Cuprous Oxide Nanocomposites

AbstractNanocomposite films of copper metal and cuprous oxide, Cu2O, are electrodeposited at room temperature from alkaline solutions of copper(II) lactate. The electrode potential oscillates spontaneously if the films are deposited galvanostatically. The oscillation period is a function of pH, varying from 69 seconds at pH 8.7 to 11 seconds at pH 9.7. No oscillations are observed if the pH is below 8.5 or above 10. The phase composition of films deposited at 0.5 mA/cm2 is a function of pH. The composition varies from nearly pure copper (93 mole%) at pH 8, to 42 mole% copper at pH 9.5, to pure cuprous oxide when the pH exceeds 10. The observation of quasi‐periodic potential oscillations suggests that the nanocomposites are layered. The calculated faradaic thickness of cuprous oxide is 5–8 nm, and the thickness of the copper layer is 1–11 nm. The thickness of each of the layers increases as the pH is lowered.

Electrodeposition of Copper / Cuprous Oxide Nanocomposites

ABSTRACTNanocomposite films of copper metal and cuprous oxide were electrodeposited at room temperature from an alkaline copper(11) lactate solution. The electrode potential oscillated spontaneously during constant-current deposition of the composites. The oscillations were periodic in a stirred solution, but became chaotic in unstirred solution. For a given current density the phase composition was a strong function of solution pH. As the pH was increased, the cuprous oxide content increased. At pH 12, no oscillations were observed, and pure cuprous oxide was deposited. At pH 9, the phase composition varied from pure cuprous oxide at current densities below 0.1 mA/cm2 to 96 mole percent copper at 2.5 mA/cm2.