Hierarchical Shelled ZnO Structures Made of Bunched Nanowire Arrays

Abstract

The size‐ and morphology‐controlled growth of ZnO nanowire (NW) arrays is potentially of interest for the design of advanced catalysts and nanodevices. By adjusting the reaction temperature, shelled structures of ZnO made of bunched ZnO NW arrays are prepared, grown out of metallic Zn microspheres through a wet‐chemical route in a closed Teflon reactor. In this process, ZnO NWs are nucleated and subsequently grown into NWs on the surfaces of the microspheres as well as in strong alkali solution under the condition of the pre‐existence of zincate (ZnO22–) ions. At a higher temperature (200 °C), three different types of bunched ZnO NW or sub‐micrometer rodlike (SMR) aggregates are observed. At room temperature, however, the bunched ZnO NW arrays are found only to occur on the Zn microsphere surface, while double‐pyramid‐shaped or rhombus‐shaped ZnO particles are formed in solution. The ZnO NWs exhibit an ultrathin structure with a length of ca. 500 nm and a diameter of ca. 10 nm. The phenomenon may be well understood by the temperature‐dependent growth process involved in different nucleation sources. A growth mechanism has been proposed in which the degree of ZnO22–saturation in the reaction solution plays a key role in controlling the nucleation and growth of the ZnO NWs or SMRs as well as in oxidizing the metallic Zn microspheres. Based on this consideration, ultrathin ZnO NW cluster arrays on the Zn microspheres are successfully obtained. Raman spectroscopy and photoluminescence measurements of the ultrathin ZnO NW cluster arrays have also been performed.

Biotemplated Hierarchical Nanostructure of Layered Double Hydroxides with Improved Photocatalysis Performance

“…Figure 4F shows the hexagonal nanocrystal ZnO with the interplanar distance of 0.28 nm, in accordance with the hexagonal wurtzite structure with the space group C 6v . 39 The results above unambiguously confirm that the wurtzite crystalline ZnO and cubic ZnAl 2 O 4 structure formed through calcination process of the biotemplated LDH film. For comparison, HRTEM images for the ZnAlϪLDH and ZnAlϪMMO powder samples were obtained (Support- Figure S4 and Figure S5, respectively).…”

A green approach towards the production of Zinc Oxide scaffolds

“…2a) and found to be 3.25 eV [6]. This value is consistent with standard bulk zinc oxide values (3.37 eV) [7]- [9]. in inset fig.…”

Simple non-basic solution route for the preparation of zinc oxide hollow spheres

“…The strong emission peak centered at 422 nm can be assigned to the recombination of an electron at Zn i and a hole in the valence band. The weak emission peak around 530 nm may be related to the singly ionized oxygen vacancy [43] and the mechanism of the emission at 485 nm is not yet clear. The absorption peak centered for 378 nm can be clearly observed (inset of Fig.…”

“…The peak at 332 cm À 1 is attributed to the 2E 2 mode. A strong intensity of the E 2 modes implies that the ZnO hollow spheres are severely oxygen deficient [43].…”