CuO Nanoribbons Research Articles

Solution-Phase Synthesis of Single-Crystal CuO Nanoribbons and Nanorings

A solution-phase route has been developed for the synthesis of single-crystal CuO nanoribbons with widths of 10−80 nm, thicknesses of 5−20 nm, and lengths ranging from several hundred nanometers to several micrometers and for nanorings with diameters of 100−300 nm. The CuO nanoribbons and nanorings were fabricated by the reaction of CuCl2 and NaOH solutions with sodium dodecyl benzenesulfonate (SDBS). The as-synthesized products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), revealing that CuO nanoribbons and nanorings had single-crystal monoclinic structures and nanorings were closed but were not the simple superposition of two ends of the nanoribbons. On the basis of TEM observations, the formation processes of nanoribbons and nanorings can be interpreted by two stages: initial nanoflakes split into nanoribbons due to the Brownian movement of surfactant molecules, and then these nanoribbons that possess polar surfaces coil into nanorings to reduce the electrostatic energy. This ringlike CuO nanomaterial may have some potential value in nanoscale applications.

Controlled synthesis of CuO nanostructures by a simple solution route

A simple solution route has been developed to prepare nanostructured CuO with Cu(NO 3) 2·3H 2O and NaOH as starting materials. CuO nanoribbons or nanorods and their assemblies into hierarchical structures have been synthesized, respectively, by controlling the molar ratio of NaOH to Cu(NO 3) 2, reaction temperature and the concentration of the starting NaOH solution. Experiments demonstrate that the molar ratio of NaOH to Cu(NO 3) 2 is an important parameter which may decide whether CuO exists in nanoribbons (nanorods) or assemblies into hierarchical structures. Whether Cu(NO 3) 2 is dissolved in ethanol or water also influences the formation of monodispersed CuO nanoribbons (nanorods). The growth mechanism of these nanostructures is discussed. The products were characterized by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy (HRTEM) and their optical absorption spectra were also studied.

Mesoscale organization of CuO nanoribbons: formation of "dandelions".

A two-tiered organizing scheme with multiple-length scales for construction of dandelion-like hollow CuO microspheres has been elucidated: (1) mesoscale formation of rhombic building units from smaller nanoribbons via oriented aggregation and (2) macroscopic organization of these units into the CuO microspheres. This self-assembly concept may also be applicable to other metal oxides by creating geometric constraints for constructional units.

Controlled Synthesis and Self-Assembly of Single-Crystalline CuO Nanorods and Nanoribbons

We report several wet-chemical methods for synthesis of one-dimensional CuO nanostructures in water−ethanol mixed solvents at 77−82 °C and 1 atm. Single-crystalline monodispersed CuO nanorods with a selected breadth in the range of 5−15 nm have been prepared by controlling reagent concentrations. The nanorods are preferentially grown along 〈010〉 directions. A two-step continuous process has also been developed to prepare CuO nanorods and ribbons (length up to 1 μm) with a large aspect ratio under pseudo-steady-state operation. Furthermore, a two-dimensional netted structure has been assembled for the first time from short nanorods formed after prolonged aging; the nanorods are attached each other using their {001}, {100}, and {110} crystal planes. With concentrated NaOH used in synthesis, the nanorods can also be extended along 〈100〉, which gives rise to the formation of CuO nanoplatelets. Various synthetic parameters have also been investigated.

Template-free synthesis of Cu2Cl(OH)3 nanoribbons and use as sacrificial template for CuO nanoribbon

Cu2Cl(OH)3 nanoribbons with an average diameter of 50nm in width and several micrometers in length have been synthesized for the first time by exploiting a template-free approach at ambient temperature. The growth mechanism and the optimization conditions to grow the Cu2Cl(OH)3 nanoribbon are investigated. The CuO nanoribbons with well-preserved structures are formed through a heat treatment of Cu2Cl(OH)3 nanoribbons. The advantages of our method for the single-crystalline Cu2Cl(OH)3 nanoribbons lie in the mild reaction conditions and simple operation, which permit large-scale production at a low cost. In addition, it provides a practical method to prepare one-dimensional CuO materials.

Synthesis of Cu(OH)2 and CuO Nanoribbon Arrays on a Copper Surface

Cu(OH)2 and CuO nanoribbon arrays aligned approximately perpendicular to copper substrate surfaces are synthesized by the solution-treatment and subsequent heat-treatment processes. The Cu(OH)2 nanoribbons are fabricated by a simple coordination self-assembly method in an alkaline solution with Cu2+ ions being from the surface oxidation of copper. The CuO nanoribbons are formed by removing water from the Cu(OH)2 nanoribbons through heat treatment. The nanoribbons are ∼50−60 nm in average width and several nanometers in thickness, and the lengths can be well-controlled by varying the reaction temperature and time interval. Transmission electron microscopy, high-resolution TEM, scanning electron microscopy, electron diffraction, and X-ray diffraction techniques have been used to characterize the microstructures and morphologies of the nanoribbon materials.