Low-temperature synthesis and photocatalytic properties of ZnO nanotubes by thermal oxidation of Zn nanowires

Abstract

A low-cost and catalyst-free two-step approach has been developed to produce ZnO nanotubes (ZNTs) by simple thermal oxidation of Zn nanowires under 20 Pa at a low temperature of 400 °C. The growth mechanism of ZNTs is discussed in detail. The formation of these tubular structures is closely linked to the oxidation pressure and temperature, which involves a process consisting of the deposition of Zn nanowires, cracking of the Zn nanowires and sublimation of the Zn cores, and subsequent oxidation to ZNTs. The optical properties were studied by using Raman and photoluminescence spectra, where a strong green emission related to the single ionized oxygen vacancy appears. The photocatalytic activity measurement indicates an enhanced photocatalytic activity of the prepared ZNTs due to their high surface-to-volume ratios and abundant oxygen vacancies near the surfaces of the ZNTs. This type of high surface area structural ZNTs could find promising potential for optoelectronic and environmental applications.

Two types of excited electron dynamics in zinc oxide

“…1,2 Besides, the doped zinc oxide manifests itself as a good photocatalyst which can be used for decomposing harmful bacteria and organic contaminants. [3][4][5] Since the optical and photocatalytic properties to a great extent depend on the dynamics of excited states, the studies of fast electron dynamics in zinc oxide have been carried out in a series of experimental works employing time-resolved optical techniques. A great part of them concerns with the dynamics of exciton states important for optical applications.…”

Metal Oxide Nanostructures: Growth and Applications

“…For 45 min of deposition time a different morphology of nanocable was observed. [55] For deposition time longer than 45 min, the formation of nanocontainers was observed.…”

“…Lu et al [55] reported the growth of ZnO nanotubes by simply thermal oxidation of zinc metal nanowires at 400 and 500°C, Fig. 5.11.…”

Synthesis and Photocatalytic Property of SnO₂/ZnO Nanorod Composites

“…Various types of ZnO micro/nanostructures have been prepared for photocatalyst applications because of their high photosensitivity and stability [8][9][10]. Owing to large specific surface area and length to diameter ratio, quasi-one-dimensional (1D) ZnO nanostructures, such as nanowires, nanorods and nanobelts, could potentially be a very good class of catalysis support structures [10][11][12].…”

“…Owing to large specific surface area and length to diameter ratio, quasi-one-dimensional (1D) ZnO nanostructures, such as nanowires, nanorods and nanobelts, could potentially be a very good class of catalysis support structures [10][11][12]. However, the high recombination rate of photogenerated electron-hole pairs has limited its commercialization of this technology.…”